# Wetsuits & Drysuits

A wetsuit trades warmth for flexibility through thickness and seam construction; a drysuit's shell material (membrane vs neoprene) decides whether buoyancy stays constant with depth and whether warmth comes from the suit or a separate undergarment. Activity adds constraints: triathlon caps thickness by rule, diving adds seals and valves.

## How it works

A wetsuit is a skin-tight layer of foamed neoprene, full of tiny gas bubbles, that lets in a thin film of water the body warms and traps against the skin; thicker foam and tighter, glued or sealed seams keep more of that warmth in at the cost of stretch. A drysuit instead keeps water out entirely with watertight seals at the neck, wrists and a sealed zipper, so the wearer stays dry and warmth comes mainly from an insulating undergarment worn underneath rather than from the suit shell itself; a neoprene-shell drysuit adds some of its own insulation and buoyancy, while a thin membrane shell adds almost none.

## How an expert narrows the choice

```mermaid
timeline
  section 1 · Wetsuit or drysuit
    wetsuit : ask Coverage style, Neoprene thickness : skip Drysuit shell material, Drysuit entry zip placement, Neck/wrist seal material, Seal attachment system, Drysuit foot system, Inflation/exhaust valve, Undergarment weight, Knee/elbow reinforcement
    drysuit : ask Drysuit shell material, Undergarment weight : skip Neoprene thickness, Seam construction, Wetsuit entry/zip style, Coldest rated water temperature
  section 2 · Main activity
    triathlon_race : ask Coldest rated water temperature : skip Neck/wrist seal material, Inflation/exhaust valve, Drysuit foot system, EN 14225 / CE marking
    surf_bodyboard : skip EN 14225 / CE marking
    openwater_swim_recreational : skip EN 14225 / CE marking
    paddlesports_sailing : skip EN 14225 / CE marking
```

1. **Wetsuit or drysuit.** A wetsuit (gets wet, insulates) or a drysuit (stays dry)?
   A wetsuit's defining specs are thickness and seam construction; a drysuit's are shell material, seals and valves. This fork decides which facet set to ask next.
   If wetsuit: ask Coverage style, Neoprene thickness; skip Drysuit shell material, Drysuit entry zip placement, Neck/wrist seal material, Seal attachment system, Drysuit foot system, Inflation/exhaust valve, Undergarment weight, Knee/elbow reinforcement.
   If drysuit: ask Drysuit shell material, Undergarment weight; skip Neoprene thickness, Seam construction, Wetsuit entry/zip style, Coldest rated water temperature.
   Skip if already known: a query that already names 'wetsuit' or 'drysuit', an earlier answer naming neoprene thickness or a membrane/trilaminate shell.

2. **Main activity.** Surfing, diving, triathlon racing, open-water swimming, or paddling/sailing?
   Activity decides what else matters: sanctioned triathlon caps thickness by rule, dive needs seals and valves on a drysuit or abrasion resistance on a wetsuit, surf wants maximum paddling flex, paddle/sail wants visibility and durability over flex.
   If triathlon_race: ask Coldest rated water temperature; skip Neck/wrist seal material, Inflation/exhaust valve, Drysuit foot system, EN 14225 / CE marking.
   If surf_bodyboard: skip EN 14225 / CE marking.
   If openwater_swim_recreational: skip EN 14225 / CE marking.
   If paddlesports_sailing: skip EN 14225 / CE marking.
   Skip if already known: an earlier answer naming surfing, scuba, freediving, triathlon, open-water swimming, kayaking or sailing.

## What to surface

### Wetsuit or drysuit

Whether the suit works by trapping a warmed film of water against the skin (wetsuit) or by keeping the wearer completely dry with sealed entry and cuffs (drysuit). It is the single biggest fork in the category: a wetsuit's warmth comes from neoprene thickness and seam tightness, while a drysuit's warmth comes mostly from an undergarment, and its failure mode (a leak) is a safety issue rather than just discomfort. [1] [2]

Values: wetsuit, drysuit.
Question to ask: A wetsuit (gets wet, insulates) or a drysuit (stays dry)?

Used as: top-level split, filter. Data: derived from listing fields, backfill cost low. Look for it as: Derive from the product title ('wetsuit' vs 'dry suit'/'drysuit') and category breadcrumb.
Title keyword match covers nearly every listing; drysuits are also usually priced well above wetsuits, which is a useful tiebreaker.

### Main activity

What the suit is mainly used for: surfing/bodyboarding, scuba diving or freediving/spearfishing, sanctioned triathlon or open-water race, recreational/unsanctioned open-water swimming, or paddle sports and sailing. Activity sets constraints beyond thickness: a sanctioned triathlon or open-water race caps wetsuit thickness at 5mm by competition rule, which doesn't apply to recreational swimming; diving adds seals and valves or abrasion resistance; paddle/sailing use favours durability and visibility over maximum paddling flex. [3] [4]

Values: surf_bodyboard, scuba_freedive_spearfish, triathlon_race, openwater_swim_recreational, paddlesports_sailing.
Question to ask: Surfing, diving, triathlon racing, open-water swimming, or paddling/sailing?

Used as: top-level split, filter. Data: derived from listing fields, backfill cost low. Look for it as: Often implied by the product's marketed category ('triathlon wetsuit', 'freediving wetsuit', 'kayak drysuit') rather than a stated field.
Keyword-match title/category against the five values; a plain 'full suit' with no activity keyword defaults to surf_bodyboard, the largest segment.

### Neoprene thickness

The suit's torso and limb neoprene thickness in millimetres, written as a single number (e.g. 2mm) or a torso/limb pair (e.g. 4/3mm, 5/4mm). Thickness is the main warmth dial: each step up (2mm, 3/2, 4/3, 5/4, 6/5) covers a lower water-temperature band but stiffens the suit and costs paddling or swimming range of motion, which is why racing wetsuits are thin even in cool water and why thickness is capped by rule in triathlon. [1] [5]

Values: 1_to_1.5mm, 2mm, 3_2mm, 4_3mm, 5_4mm, 5_4_3mm, 6_5mm_or_thicker.
Question to ask: What thickness, in mm (like 3/2 or 4/3)?

Used as: filter, shown on the card, sortable. Data: on the listing, backfill cost low. Look for it as: Almost always in the title as an 'X/Ymm' or 'Xmm' figure.
Title regex match for patterns like '4/3mm', '5mm'; default to 3_2mm (the most common all-rounder) when unstated.
Chart: position on the warmth-vs-flexibility axis, thinnest on the flexible end.

### Coverage style

How much of the body the wetsuit covers and in what shape: spring suit/shorty (short arms and legs), long john/farmer john (torso and legs, no sleeves), jacket/vest (torso only), full suit/steamer (full arms and legs), or semi-dry (a full suit with sealed cuffs). Coverage is the first-order warmth decision before thickness even enters: a 2mm shorty in warm water and a 5mm full suit in cold water are not interchangeable regardless of neoprene grade, and a semi-dry adds sealed cuffs on top of a full suit for extra warmth without the complexity of a drysuit. [1]

Values: spring_suit_shorty, long_john_farmer_john, jacket_vest, full_suit_steamer, semi_dry.
Question to ask: Short arms and legs, a vest, or full coverage?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Almost always in the title or product type ('Shorty Spring Suit', 'Full Suit Steamer', 'Semi-Dry Wetsuit').
Title keyword match; default to full_suit_steamer when unstated since it is the most common configuration.

### Coldest rated water temperature

The coldest water temperature, in degrees Fahrenheit, the suit's thickness class is generally recommended for. This is the number that actually answers the buyer's question ('will I be warm enough'), and it is what thickness_class is a proxy for: three independent brand/retailer charts put 3/2mm at roughly 59 to 65°F, 4/3mm at 52 to 58°F, 5/4mm at 45 to 51°F, and 6/5mm-plus below 45°F. [5] [6] [7]

Range: 3/2mm suits are recommended down to about 59°F, 4/3mm down to about 52°F, 5/4mm down to about 45°F, and 6/5mm or thicker below that.
Question to ask: Roughly how cold is the water, in °F?

Used as: shown on the card, sortable. Data: needs research, backfill cost low. Look for it as: Rarely a stated spec field; derive from thickness_class using the chart in why_experts_care.
Derive deterministically from thickness_class; no per-listing lookup needed.
Chart: position on a horizontal temperature scale, coldest on the left.

### Seam construction

How the neoprene panels are joined: flatlock or overlock stitching (fully pierced, not watertight), GBS (glued and blind-stitched, needle only goes halfway through), or GBS with an added liquid-sealed and/or internally taped seam. This is the cheapest lever a brand has to add or remove warmth: flatlock seams let water flow through and are only acceptable above roughly 65°F, GBS is the standard for anything meant for cold water, and sealed/taped seams on top of GBS are what separates a premium cold-water suit from a mid-range one at the same thickness. [9] [8]

Values: flatlock_or_overlock, gbs_glued_blind_stitched, gbs_sealed, gbs_sealed_taped.
Question to ask: Do the seams need to be fully watertight?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Named on brand spec pages ('flatlock', 'GBS', 'liquid taped seams'); rarely in the retail title except for budget flatlock suits.
Keyword match the description; suits under about 2.5mm with no seam claim default to flatlock_or_overlock, suits 3mm+ with no claim default to gbs_glued_blind_stitched.
Chart: position on a warmth/water-tightness axis, flatlock at the low end.

### Hood

Whether the suit has a hood integrated into the suit, a hood that attaches/detaches, or no hood at all. A significant share of body heat is lost through the head in cold water, so hooded configurations exist specifically for the coldest bracket (roughly below 48°F); an attached hood seals better than a separate accessory hood worn underneath a suit's neck opening. [1] [5]

Values: none, attached_integrated, detachable, separate_accessory_not_included.
Question to ask: Does it come with a hood built in?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Usually in the title for hooded suits ('Hooded Full Suit', '5/4 Hooded').
Title keyword match for 'hooded'; default to none when unstated.

### Drysuit shell material

What the drysuit's waterproof shell is made from: a thin membrane (trilaminate fabric or vulcanized rubber-coated fabric), foamed neoprene (standard or compressed/crushed), or a hybrid combining both. This is the defining drysuit spec: a membrane shell has almost no insulation of its own and does not compress with depth, so buoyancy stays constant and warmth depends entirely on the undergarment; a neoprene shell adds its own insulation and a form-fitting feel but compresses at depth, losing both insulation and buoyancy as the dive gets deeper. [2] [12]

Values: membrane_trilaminate, membrane_vulcanized_rubber, foamed_neoprene, compressed_crushed_neoprene, hybrid.
Question to ask: A thin waterproof membrane, or insulating neoprene?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Named on brand spec pages ('trilaminate', 'crushed neoprene'); usually in the product title for dive-market drysuits.
Keyword match the title/description against the five values; a plain 'neoprene drysuit' with no further qualifier defaults to foamed_neoprene.
Chart: position on an insulation-vs-buoyancy-stability axis, membrane at the stable-buoyancy end.

### Neck/wrist seal material

What the neck and wrist seals are made from: latex rubber, silicone rubber, or foam neoprene. Latex seals are the most watertight and comfortable when new but tear easily, degrade with oil and sun exposure, and need replacing every couple of years; silicone seals cost more up front but resist that degradation and are not as easily nicked; neoprene seals are the most durable and least allergenic but seal less tightly, so they let in more water around the neck and wrists. [2]

Values: latex, silicone, neoprene_foam.
Question to ask: Latex, silicone, or neoprene seals?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Usually named on the drysuit's spec sheet; rarely in the retail title.
Keyword match the description; default to latex, the most common recreational seal material, when unstated.
Chart: position on a durability-vs-seal-tightness axis, latex at the tight-seal end.

### Inflation/exhaust valve

Whether the drysuit has a gas inflator valve plus an exhaust/dump valve for managing suit squeeze and buoyancy underwater, or no inflation system at all. A diving drysuit needs an inflator and dump valve to add gas as depth increases (preventing 'suit squeeze') and vent it on ascent (preventing an uncontrolled rapid rise); a drysuit built for surface use only (kayaking, sailing, wading) has no reason to carry this system and is simpler and cheaper without it. [2]

Values: inflator_and_dump_valve, none_surface_use_only.
Question to ask: Will you be diving below the surface in it?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Named on dive-market drysuit spec sheets; surface-use drysuits (kayak/sailing) generally state they have no inflation valve.
Infer from primary_activity: scuba_freedive_spearfish defaults to inflator_and_dump_valve, other activities default to none_surface_use_only.

### Knee/elbow reinforcement

Whether the drysuit has extra padding or abrasion-resistant material sewn onto the knees, elbows and seat. These are the first points to wear through on a drysuit from kneeling, crawling or working against rough surfaces, so reinforcement is a durability spec rather than a warmth one; its absence is a common reason a recreational-grade suit fails early on commercial or technical divers. [2]

Values: reinforced_knee_elbow_pads, none_or_unspecified.
Question to ask: Will you be kneeling or crawling on rough surfaces in it?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Usually named in bullets ('reinforced knee pads', 'Kevlar knee patches').
Keyword match for 'reinforced' plus a body-part term; default to none_or_unspecified when absent.

### Neoprene source

What the foamed neoprene is made from: standard petroleum-derived neoprene, limestone-derived neoprene, a named premium limestone grade (e.g. Yamamoto), or Yulex plant-based natural rubber. Petroleum neoprene is the cheapest and most common baseline; limestone neoprene and especially Yamamoto grades stretch more and recover better for the same thickness, which is why they sit in the $300+ tier; Yulex trades some of that stretch for a non-petroleum, lower-emission material. [8]

Values: petroleum_neoprene, limestone_neoprene, yamamoto_premium_limestone, yulex_natural_rubber, unspecified.
Question to ask: Standard neoprene, limestone-based, or plant-based rubber?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Named on brand spec pages and often in the title for premium suits ('Yamamoto', 'Yulex', 'Eco Prene'); unstated on budget suits usually means petroleum_neoprene.
Keyword match the title/description against named materials; default to petroleum_neoprene when nothing is named, since it is the least-marketed, most common base material.
Chart: position on a stretch/price axis, petroleum neoprene at the low end.

### Interior lining

What faces the skin on the inside of the suit: a nylon jersey weave, a thermal plush/fleece lining, a smoothskin (no fabric lining) surface, or a graphene-infused thermal lining. Lining decides how fast the suit traps warmth and how it feels going on: thermal plush and graphene linings warm up almost instantly against skin and are reserved for cold-water torso panels, while smoothskin (no lining) cuts wind-chill on the outside but is delicate and easily nicked. [8]

Values: nylon_jersey, thermal_plush_fleece, smoothskin, graphene_thermal, unspecified.
Question to ask: Does the inside feel like soft fleece, or smooth rubber?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Named on brand spec pages ('thermal plush lining', 'Graphene Infinity'); rarely in the retail title.
Keyword match the description against named linings; default to nylon_jersey, the baseline lining, when unstated.

### Wetsuit entry/zip style

How the wetsuit is closed and entered: a vertical back zip, a chest zip with little or no zip (zipperless), or a vertical front zip. A back zip is easiest to get in and out of alone but is the largest single leak path for water and lets in the most flush; chest-zip and zipperless designs seal better and flex more at the shoulders but are harder to put on without help. [1]

Values: back_zip, chest_zip_or_zipperless, front_zip.
Question to ask: Easiest to put on alone, or warmest at the shoulders?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Usually named in the title or bullet points ('Back Zip', 'Chest Zip', 'Zip Free').
Title keyword match; default to back_zip, the most common entry style, when unstated.

### EN 14225 / CE marking

Whether the suit is CE-marked as personal protective equipment under EN 14225-1 (wetsuits) or EN 14225-2 (drysuits), the European construction, thermal and performance standard for diving suits. EN 14225 is the governing standard for diving suits sold in the EU: it requires immersive thermal resistance, tensile strength and practical performance testing, and CE marking under PPE regulation (EU) 2016/425; it explicitly does not cover gloves, hoods or boots sold separately, or snorkelling-only suits, so a CE mark on a suit says nothing about those accessories. [10] [11]

Values: ce_marked_en14225, not_ce_marked_or_unstated.
Question to ask: Is it CE-marked as diving PPE (EN 14225)?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Stated on EU-market dive-oriented listings as 'CE EN 14225' or similar; almost never stated on surf-market listings even though the suit may still meet it.
Keyword match for 'CE' and '14225' in the description; default to not_ce_marked_or_unstated when absent, since absence of the mark is common even on compliant suits sold outside the EU.

### Drysuit entry zip placement

Where the watertight entry zipper sits: diagonally across the front/chest, or across the back of the shoulders (rear/shoulder entry). A front/diagonal zip can usually be self-donned and reached for mid-dive adjustments; a rear/shoulder-entry zip almost always needs help to close but keeps the zip off the chest, out of the way of harness and BCD straps and clear of abrasion on rocky entries. [2]

Values: front_diagonal_entry, rear_shoulder_entry.
Question to ask: Will you usually have someone to help you zip in?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Usually named in the title or bullets ('front entry', 'rear zip', 'self-donning').
Title keyword match; default to front_diagonal_entry, the more common recreational configuration, when unstated.

### Seal attachment system

Whether the neck and wrist seals are permanently glued/stitched to the suit, or mounted on a quick-change ring system that lets the wearer swap seals without tools. A glued/stitched seal is cheaper but must go back to a repair shop when it tears; a quick-change ring system costs more up front but lets the diver carry a spare seal and swap a torn one in minutes, which matters most for seals made of fragile latex. [2]

Values: glued_or_stitched_fixed, quick_change_ring_system.
Question to ask: Fixed seals, or swappable without tools?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Named on the drysuit's spec sheet when present ('quick-change rings', 'Si-Tech rings'); its absence usually means fixed seals.
Keyword match for ring-system brand names and 'quick-change'; default to glued_or_stitched_fixed when unstated.

### Drysuit foot system

Whether the drysuit has heavy-duty integral boots built into the suit, lightweight integral boots, or latex ankle socks meant to be worn inside separate dive boots. Integral boots are simpler and warmer but are sized to the suit, not the foot, so fit compromises are common; latex socks under separate boots let the diver choose boot stiffness and sole grip independently, at the cost of an extra ankle seal that can leak. [2]

Values: integral_boots_heavy_duty, integral_boots_lightweight, latex_socks_separate_boots.
Question to ask: Built-in boots, or socks you pair with separate boots?

Used as: filter, shown on the card. Data: on the listing, backfill cost low. Look for it as: Usually named in the title or bullets ('attached boots', 'latex socks').
Title keyword match; default to integral_boots_lightweight, the common recreational default, when unstated.

### Undergarment weight

The thermal undergarment the drysuit is designed to be worn with, roughly graded by loft/weight: base-layer only, midweight fleece, or heavyweight insulated. Since a membrane drysuit provides almost none of its own insulation, the undergarment is doing most of the warmth work; picking too light an undergarment for the water temperature is the most common reason a drysuit diver gets cold, independent of the suit shell itself. [2]

Values: base_layer_only, midweight_fleece, heavyweight_insulated, not_applicable_builtin_neoprene.
Question to ask: How cold is the water you'll be diving in?

Used as: filter, shown on the card. Data: needs research, backfill cost high. Look for it as: Rarely a field on the suit listing itself; undergarments are usually sold and specified separately by weight/loft.
Not reliably inferable from the suit listing alone; default to midweight_fleece as a general recommendation when shell_material is membrane_trilaminate or membrane_vulcanized_rubber, and not_applicable_builtin_neoprene when shell_material is foamed_neoprene.

### Neoprene stretch/flex grade

How much the neoprene itself stretches, independent of thickness: a standard-stretch grade, a high-stretch grade (often on shoulder/back panels), or the highest-stretch grade a line offers (e.g. Yamamoto #39 vs #40/#45). Two suits at the same thickness can feel very different to paddle in: brands tier their own lineups mainly by swapping in a higher-stretch neoprene grade on the same panels, trading some durability for shoulder and back flexibility rather than changing warmth. [5] [8]

Values: standard_stretch, high_stretch, highest_stretch, unspecified.
Question to ask: Standard, high-stretch, or highest-stretch neoprene panels?

Used as: filter, shown on the card. Data: needs research, backfill cost medium. Look for it as: Named on brand spec sheets as a stretch-grade term ('high-stretch', 'highest-stretch') or a Yamamoto grade number; rarely in the retail title.
Keyword/number match against stretch-grade terms and Yamamoto numbers (lower numbers stiffer, #39+ stretchier); default to standard_stretch when none is named.
Chart: position on a stretch-vs-durability axis, standard_stretch at the durable end.

## What you give up

- Every step up in thickness or seam tightness traps more warmth but stiffens the suit; a surfer paddling or a swimmer reaching will feel a 5/4mm sealed suit fight them in a way a 3/2mm flatlock suit never does, which is why racing and warm-water suits stay thin even when a thicker suit would be more comfortable standing still. [1] [5] Board branch: "Warmer, less flexible suits".
- Flatlock seams are fully stitched through, which is cheap and flexible but lets water flow straight through the seam; GBS and sealed/taped seams glue and only half-stitch the panels, which costs more to make but is what makes a suit usable below about 65°F instead of just a warm-water layer. [9] [8] Board branch: "Fully sealed cold-water construction".
- A membrane shell doesn't compress with depth, so buoyancy stays predictable and the suit packs small, but it has almost no insulation of its own and the diver is cold without the right undergarment; a neoprene shell is warmer straight out of the bag and feels more form-fitting, but it compresses as depth increases, so both its insulation and its buoyancy shrink on the way down. [2] [12] Board branch: "Neoprene-shell drysuits with built-in insulation".

## Words you will meet

- **Neoprene**. A synthetic rubber foamed with tiny gas bubbles, which is what makes wetsuits and most drysuit shells buoyant and insulating.
- **GBS (glued and blind-stitched) seam**. A seam where the panels are glued together and then stitched only halfway through the neoprene, so the seam stays mostly watertight.
- **Flatlock seam**. A seam stitched all the way through both panels, which is flexible and cheap but lets water pass straight through.
- **Trilaminate**. A three-layer fabric (often nylon and butyl rubber) used as a thin, non-stretch waterproof drysuit shell.
- **Latex seal**. A thin natural-rubber ring at a drysuit's neck or wrist that stretches to seal against the skin.
- **Dump valve**. A one-way valve on a drysuit that lets excess gas vent out so the diver doesn't rise too fast as they ascend.
- **Inflator valve**. The valve a diver uses to add gas into a drysuit as depth increases, to stop the suit from squeezing against the skin.
- **Undergarment**. The insulating layer worn underneath a drysuit, since the shell itself (especially a membrane shell) provides little warmth on its own.
- **Steamer**. A one-piece, full-arm, full-leg wetsuit, named for the visible water vapour it gives off when removed.
- **Long john / farmer john**. A sleeveless wetsuit covering the torso and legs, like bib overalls, usually worn under a separate jacket.
- **Shorty / spring suit**. A short-armed, short-legged wetsuit covering just the torso, thighs and upper arms, for warm water.
- **Semi-dry suit**. A wetsuit with extra-tight seals at the neck, wrists and ankles plus a near-watertight zip, reducing water flush without going fully dry.
- **Yamamoto neoprene**. A Japanese limestone-based neoprene brand that wetsuit makers grade by number for density and stretch; a common marker of a premium suit.
- **Yulex**. A branded, FSC-certified natural rubber made from the hevea tree instead of petroleum or limestone, used as a wetsuit neoprene alternative.
- **Smoothskin**. A smooth rubber neoprene surface with no fabric lining on the outside, which cuts wind-chill but tears more easily than a jersey-covered panel.
- **Compressed/crushed neoprene**. Foamed neoprene pre-compressed to collapse some of its gas bubbles, so it holds a steadier buoyancy and insulation at diving depth than standard foamed neoprene.
- **CE marking (EN 14225)**. A European mark showing a diving suit passed construction, thermal and performance testing under the EN 14225 standard.
- **Suit squeeze**. The painful pinching that happens when gas in a drysuit (or its undergarment) compresses with depth faster than the diver adds more gas.

## Where we made a call

- Competition rules, not buyer preference, cap triathlon/open-water-race wetsuit thickness at 5mm and set the water-temperature cutoffs for when wetsuits are legal. (confidence high). Confirmed independently by a brand's own rules page and a triathlon-training site both quoting USAT/IRONMAN limits; both cite the same 5mm figure and a 24.5°C/76.1°F cutoff. [3] [4]

## References

1. [Wetsuit](https://en.wikipedia.org/wiki/Wetsuit) (primer). Supports: Defines spring suit/shorty, long john, jacket, full suit/steamer and semi-dry configurations; Thickness is specified as torso/limb pair (e.g. '5/3'); thicker suits restrict mobility; Back, chest and front zip closures and their leak/flex trade-offs; Hooded configurations exist for the coldest water bracket.
2. [Drysuit](https://en.wikipedia.org/wiki/Drysuit) (primer). Supports: Membrane shells have little insulation and need a thermal undergarment; Neoprene drysuit seals/zip/inflator/wrist seal/vent components; Latex, silicone and neoprene-foam seal materials and their durability trade-offs; Quick-change attachment rings for seals; Integral boots vs latex socks worn with separate boots; Inflator and dump (exhaust) valves manage suit squeeze and ascent rate; Front/diagonal vs rear/shoulder-entry zipper placement; Reinforcement and padding on knees, elbows and seat for durability.
3. [Wetsuit & Speedsuit Rules](https://www.xterrawetsuits.com/pages/wetsuit-speedsuit-rules) (spec sheet). Supports: Triathlon wetsuit thickness may not exceed 5mm; Wetsuits permitted up to 24.5°C/76.1°F water temperature, mandatory below 16°C.
4. [Triathlon Wetsuit Temp In-Depth Guide](https://trinewbies.com/triathlon-wetsuit-temperature-guide/) (specialist review). Supports: Independently confirms the 5mm thickness cap and 76.1°F/24.5°C cutoff via IRONMAN guidelines.
5. [Wetsuit Thickness Guide](https://www.vissla.com/pages/wetsuit-thickness-guide) (specialist review). Supports: Water-temperature-to-thickness chart from 2mm spring suit (66°F+) to 6/5mm hooded (below 45°F); Hoods become critical below roughly 48°F.
6. [Wetsuit Guide: Wetsuit Thickness](https://www.cleanlinesurf.com/pages/wetsuit-guide-wetsuit-thickness) (specialist review). Supports: Second independent water-temperature-to-thickness chart corroborating the same bands in °F.
7. [Wetsuit Thickness Guide](https://www.softboardcenter.com/en/pages/wetsuit-thickness-guide) (specialist review). Supports: Third independent water-temperature-to-thickness chart in °C, corroborating the same bands.
8. [Wetsuit Materials Explained: Neoprene Types, Limestone, and Yamamoto](https://wetsuitcenter.com/learn/wetsuit-materials-explained/) (specialist review). Supports: Petroleum vs limestone vs Yamamoto vs Yulex neoprene positioning; Lining types: nylon jersey, thermal plush, smoothskin, graphene thermal; Material/seam mix typical of each price tier.
9. [Wetsuit Seams knowledge base](https://srface.com/knowledge-base/wetsuit-seams/) (specialist review). Supports: Flatlock seams let water through and are unsuitable for winter wetsuits; GBS (glued and blind-stitched) is the standard cold-water seam; can be further liquid-sealed and/or internally taped.
10. [I.S. EN 14225-1:2017 Diving suits - Part 1: Wet suits](https://www.intertekinform.com/preview/293947678319.pdf?sku=856231_SAIG_NSAI_NSAI_2036874) (standards body). Supports: EN 14225-1 scope: construction and performance (incl. thermal) requirements for diving wetsuits; Gloves, hoods and boots, and snorkelling-only suits, are explicitly excluded from the standard's scope.
11. [Testing Wet Suits According to EN 14225-1 for CE Marking](https://cms.tecnalia.com/uploads/2023/05/Testing-Wet-Suits-According-EN-14225-TECNALIA.pdf) (standards body). Supports: CE marking of diving/surface wetsuits under EN 14225-1 and PPE regulation (EU) 2016/425; Required tests include immersive thermal resistance, tensile strength and practical performance testing.
12. [Choosing a Diving Drysuit](https://www.mikesdivestore.com/pages/choosing-a-diving-drysuit) (specialist review). Supports: Membrane drysuits: no buoyancy fluctuation from compression, negligible own insulation, need an undergarment; Neoprene drysuits: thermally insulating and form-fitting, but compress and lose insulation/buoyancy with depth.