It is the single most common question new divers and surfers ask, yet it’s rarely discussed openly: what to wear under a wetsuit. As we settle into 2026, material technology has evolved, but the fundamental dilemma remains-do you go commando, or is there specific gear that enhances the experience?
Whether you are renting a suit for a one-off lesson or breaking in your own brand-new gear, the layer sitting directly against your skin dictates your comfort level for the entire session. The wrong choice leads to painful chafing, awkward bunching, and limited mobility. The right choice feels like a second skin.
In this guide, we will cover everything from hygiene protocols for rental suits to the latest thermal base layers for cold water. If you are still in the market for your primary outer layer, make sure to check out The Ultimate Wetsuit Buying Guide for 2026: Thickness, Fit, and Style to ensure you have the perfect foundation before worrying about the undergarments.
The Short Answer: Do You Wear Anything Under a Wetsuit?
The Direct Answer
Yes, most people wear something under their wetsuit. While going "commando" (wearing nothing) is an option for those who own their suits, wearing a thin, tight-fitting layer is the standard practice for comfort, hygiene, and modesty.
Here is the quick breakdown of 2026 standards:
- Men: Compression shorts or tight swim briefs (Speedos). Avoid loose boardshorts.
- Women: Sports bikini (no knots/ties), one-piece swimsuit, or compression activewear.
- Cold Water: Thermal rash guards or neoprene heaters.
- Rentals: ALWAYS wear swimwear under a rental suit for hygiene.
Key Takeaways
| Scenario | Recommended Undergarment | Why? |
|---|---|---|
| Surfing (Warm) | Compression shorts / Bikini | Prevents rash, keeps you secure during wipeouts. |
| Diving (Deep/Cold) | Thermal Rash Guard / Skin | Adds thermal retention; wetsuits compress at depth. |
| Rental Gear | Full Swimwear | Hygiene. You don't know who wore it last. |
| Shorty Wetsuit | Modest Swimwear | Legs are exposed; ensures coverage during movement. |
For a deeper dive into how tight your suit should actually be, refer to our Wetsuit Thickness Guide to understand how fit impacts the need for underlayers.
Why Not Just Wear Boardshorts?
If you are transitioning from beach lounging to surfing, you might be tempted to just pull a wetsuit over your boardshorts. Don't do it.
- Bunching: Loose fabric rides up your legs as you pull the tight neoprene on. This creates uncomfortable lumps that can cut off circulation or chafe your thighs.
- Rash: The seams of standard boardshorts are not designed to be pressed against skin by a 3mm layer of neoprene. This friction causes severe chafing.
- Cold Spots: Wrinkled fabric creates pockets where cold water can pool, reducing the thermal efficiency of the suit.
Just as you wouldn't wear jeans under ski pants (check our Ski Length Calculator if you're planning a winter trip next), you shouldn't wear loose clothing under a wetsuit. Precision fitting is key in 2026's outdoor sports.
Best Wetsuit Undergarments for Men
For men, the goal is support without bulk. Here are the top contenders:
1. Compression Shorts (The Gold Standard)
In 2026, compression shorts specifically designed for water sports are the go-to. They prevent chafing between the thighs and keep everything secure without the "dental floss" feel of a brief. Look for synthetic blends (Lycra/Spandex) that dry quickly.
2. Swim Briefs / "Speedos"
Classic, effective, and minimal. There is zero fabric to bunch up. If you are comfortable wearing them, they are functionally the best option for fitting under a tight wetsuit.
3. Diving Skins
For scuba divers, a full-body lycra skin helps you slide into the wetsuit effortlessly. It also provides a barrier against jellyfish if you take the wetsuit off between dives.
Best Wetsuit Undergarments for Women
Women face a few more variables, specifically regarding clasps, ties, and coverage.
1. The "Surf Bikini"
Avoid bikinis with side ties, knots, or metal clasps. When a tight wetsuit presses a knot into your hip bone for two hours, it becomes agonizing. Opt for "seamless" sports-style bottoms and tops.
2. One-Piece Swimsuits
Pros: stays in place, offers full coverage if you unzip the wetsuit to cool down. Cons: Bathroom breaks are difficult. You have to take the wetsuit and the swimsuit off.
3. Activewear Tops / Sports Bras
A synthetic sports bra (not cotton) is often more comfortable than a bikini top because it offers better support and flatter seams.
4. Rash Guards
Wearing a rash guard under a wetsuit is increasingly popular in 2026. It protects sensitive skin from the neoprene texture and makes sliding the arms of the suit on much easier.
Thermal Layers: Boosting Warmth
If you are pushing the limits of your wetsuit in colder waters, a standard swimsuit won't add warmth. You need thermal base layers.
- Thermal Vests: Neoprene vests with hood attachments can be worn under a standard steamer to add core warmth.
- Poly-fleece Skins: These wick moisture away from the skin and add a layer of insulation, similar to base layers for hiking.
If you find yourself needing multiple thermal layers, your wetsuit might be too thin for the season. Always cross-reference with our Wetsuit Thickness Guide to ensure your primary gear is up to the task.
Hygiene and The Rental Rule
If you own your wetsuit, going commando is a personal choice. Many surfers prefer the freedom and direct contact with high-quality 2026 neoprene, which is softer than previous generations.
However, if you are renting:
- Rule #1: Wear a barrier. Rental suits are washed, but they are communal property. Protect yourself and the next user.
- Rule #2: Rash guards are your friend. Rental suits are often older and rougher. A full rash guard protects your skin from older, stiffer neoprene.
Caring for Undergarments
Saltwater and chlorine destroy Lycra over time.
- Rinse immediately: Just like the wetsuit, rinse your underlayers with fresh water.
- Dry in shade: UV rays break down the elasticity in compression shorts and bikinis.
- Avoid harsh detergents: Use gentle cleansers designed for activewear.
Deciding what to wear under a wetsuit ultimately comes down to two factors: personal comfort and the type of suit you are using. For the vast majority of water sports enthusiasts in 2026, a high-quality pair of compression shorts or a seamless sports bikini offers the perfect balance of protection and freedom.
Remember, the goal is to feel like the suit isn't even there. If you are constantly adjusting your base layer, it’s time to switch it up. Whether you are donning a shorty for a summer surf or layering up for a deep dive, starting with the right foundation ensures you stay focused on the adventure, not your gear. For more tips on getting that perfect fit, don't forget to revisit The Ultimate Wetsuit Buying Guide for 2026.