Keeps you visible among the waves.
11 best wetsuits for open water swimming and triathlons
Not a technical wetsuit
Tested by Yanar Alkayat, Jodie Morrish and The Runner’s World Editors
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Yamamoto 38 neoprene triathlon or adding open-water swimming to your cross-training routine? Then you're probably going to need one of our expert-tested wetsuits to train in.
The best wetsuits offer a layer of insulation against Britain's infamously chilly waters, allowing you to swim in comfort for longer, while also providing some buoyancy and protection against any floating debris.
The best wetsuits at a glance
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Training for a race? How to take your training on holiday
Orca Women's Openwater Core Hi-Vis Wetsuit
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The winning wetsuits that earned our teams seal of approval are stamped with the
Zone3 Women’s Aspect 'Breaststroke' Wetsuit
Read review
What should I look for in a wetsuit?
The best wetsuit for you will depend on what you want to use it for, as competitive triathletes will have more demands than casual paddlers. That said, there are some common key factors to consider.
Fit
Quite simply, your wetsuit will be useless if it doesn’t fit snugly – loose areas around the joints are an open invitation for flushing.
Flexibility
Wetsuits for open water swimming should have plenty of stretch around the knees, hips and shoulders. If you can’t raise your arm past your ear, then front crawl is a no-go.
Thickness
Wetsuits come in varying thicknesses for use in different seasons. This is usually displayed as two numbers separated by a slash or colon.
For example, 3:2 suits are among the most popular in the UK. The first figure represents the thickness of the torso (in millimetres) and the second, the thickness of the limbs (also in millimetres). The arms and legs tend to be thinner to allow for greater flexibility.
Buoyancy
Thanks to their thick neoprene build, wetsuits will provide a bit of extra buoyancy. But there’s a touch more to it than that. Wetsuits with thick buoyancy panels on the hips and legs are great for beginners, as they will lift your lower body in the water, placing you in a more powerful position for front crawl.
Stronger, more experienced swimmers, however, may find their legs are lifted too high by these panels. Triathletes are likely to prefer a neutral buoyancy that will allow the legs to rise and fall in the water more naturally.
What thickness wetsuit is best for swimming?
For swimming in Britain, a 2.5mm torso is best suited to tepid summer waters, 3.5 or 4mm will keep you cosy in spring and autumn, and 5mm will help keep the cold at bay in winter (providing there’s not a dusting of snow on the beach).
British Triathlon Federation race rules state that wetsuits must not exceed 5mm in thickness, but don't worry too much about this – most major brands will have taken it into account when manufacturing their wetsuits.
Dont use in really cold temperatures
Our Runner’s World Lab testers took a range of wetsuits out for a series of swims, submerging themselves in ponds, lakes and the sea in the name of research.
They then fed back on each wetsuit's performance, letting us know if they kept them warm and proved flexible enough for a race-winning front crawl.
The best models fitted like a glove and offered plenty of protection from the cold, allowing our testers to stay in the water for longer. They were stretchy enough to let them swim freely, and they didn’t dig in or chafe.
The winning wetsuits that earned our team's seal of approval are stamped with the Runner's World The arms are a bit tight to put on.
The remaining suits below have been tested and rated by our editors and contributors, all of whom swim in open water regularly and compete in triathlons. Some of these wetsuits are a little more technical – and therefore more expensive – than the wetsuits we tested in the lab, making them better suited to more competitive swimmers and experienced triathletes.
The best wetsuits to shop in 2025
Orca Women's Openwater Core Hi-Vis Wetsuit
Pros
- Keeps you visible among the waves
- Health & Injuries
Cons
- Essential guide to open-water swimming
Now we’ve told you what makes a good wetsuit, it’s time to give you an example. In true Blue Peter fashion: here’s one Orca made earlier. This hi-vis suit’s USP is its bright orange panels, which reassured our testers as it made them easier to spot from the shore.
It also nailed the basics. The stretchy Yamamoto neoprene was easy to slip in and out of while still providing that vital tight fit, and our team’s shoulders were able to move freely, whatever their stroke. The relatively thin fabric still kept them comfortable, and there was no digging in or chafing.
Currently only available in women's sizes.
| Material | Yamamoto neoprene, Infinity skin high-end lining |
|---|---|
| Thickness | 2:5:2 |
| Colours | Black/orange |
| Fit | Women |
Pros
- Expert Tested logo
- Sporty fit
Cons
- Q&A: Alice Hector
This slightly thicker suit is sure to keep you warm in cooler waters, yet the 4mm-neoprene is still lightweight and flexible — ideal for speedy swims. The buoyancy panels in the legs and hips were helpful, too, moving newer swimmers into a better position in the water.
Our team praised the sporty design and said the stretchy material helped create a great fit, particularly for taller testers. It also allowed them a full range of motion. They found the zip tricky to do up without a helping hand, however, and the arm holes a bit tight to squeeze into. But, once on, it definitely delivered.
Key specs
| Material | Speedflo neoprene, smoothskin neoprene |
|---|---|
| Thickness | 4:2 |
| Colours | Black/neon blue |
| Fit | Men and women |
Nabaiji Neoprene Open-Water Swimming Wetsuit 4/2mm
Pros
- Rubber, polyamide, elastane, polyurethane
- Excellent buoyancy
Cons
- Some may find it a little loose around the neck and groin
Thicker than most suits we trialled, this offering from Nabaiji made sure our testers didn’t freeze in some unforgiving spring waters. Instead, they were kept at a pleasant temperature throughout their swimming sessions as the neoprene effectively trapped a warm layer of water.
Some testers said they felt a little bit of flushing around the neck and groin, but most were well protected from the cold. Following feedback from previous customers, Decathlon advises buying a size up.
Key specs
| Material | Yamamoto 38 neoprene |
|---|---|
| Thickness | 4:2 |
| Colours | Black |
| Fit | Men and women |
Pros
- Updated: 29 May 2025
- The arms are a bit tight to put on
Cons
- Don't use in really cold temperatures
Previously known as the Orca S7 and renamed the Athlex Float as part of a rebrand by Orca this spring, this high-elasticity suit is designed to give swimmers who need it extra buoyancy in the water.
Our testers described it as, ‘a total joy to swim in'. It was incredibly comfortable and felt in no way restrictive, thanks to the thinner layer of neoprene in the upper body. In the legs, you’ve got a thicker 4.5mm of neoprene to keep your legs elevated and our swimmers confirmed it helped them stay afloat.
It’s a cinch to slide on and off. The back zip is easy to reach and it comes with gloves to prevent you snagging your nails on the neoprene – super handy for speedy triathlon changeovers. The snug fit and absence of bulging meant no flushing was reported and it dried in a flash, so you can use it daily.
A few panellists did get a little chilly during longer swims on cold days, but the suit is designed for use in warmer temps so that’s hardly a deal-breaker. A great choice for newer triathletes.
Key specs
| Material | Dont use in really cold temperatures |
|---|---|
| Thickness | 4.5Much easier to put on than a full wetsuit |
| Colours | Red/black, Grey/black |
| Fit | Men and women |
Zone3 Women’s Aspect 'Breaststroke' Wetsuit
Pros
- Best wetsuit overall
- Comfortable and warm
Cons
- Stretchy and easy to put on
The second Zone3 offering in this round-up, this suit has been specifically designed for swimmers who are partial to breaststroke (if you hadn’t guessed by the name). It features high-stretch panels around the shoulders and groin for totally unrestricted movement and has minimal buoyancy in the lower legs for the perfect breaststroke position.
Our testers barely noticed they had it on thanks to the comfortable, flexible fit and they didn’t experience any digging in, chafing or gaping. ‘It’s the most comfortable wetsuit I’ve ever worn!’ said one satisfied swimmer. It kept everyone warm during long stints in even the chilliest of waters and testers loved the pops of colour on the arms for style and safety.
Any downsides? The cuffs are rather tight so you won’t be able to wear a fitness tracker under the suit, and you may need a helping hand getting it on. That wouldn’t stop our panel reaching for it again, though.
Key specs
| Material | Neoprene |
|---|---|
| Thickness | N/A |
| Colours | Black/pink |
| Fit | Women's and men's |
Pros
- Best for casual swimmers
- Gender-specific fit
Cons
- Ironman Weymouth 70.3: Race Report
HUUB is known for creating endurance swimwear tailored for triathletes and open water swimmers with a focus on flexibility and speed. The Araya wetsuit delivers on both fronts, plus it's comfortable to boot.
The 2:4 buoyancy profile offers more lift in the legs, while the top stretches easily with every stroke. And yes, while putting on any wetsuit is never a walk in the park, we'd say this felt easier to pull on than a lot of others we've tested. There's also a long zip pull, plus the neck isn't too high — a feature we liked as having something tight against the throat when swimming can be uncomfortable.
On the sizing front, the women's version has been cleverly designed specifically for the female body, with more room in the midsection and extra support around the thighs and bum. Unsure which size to take, or on the taller side? The brand recommends going up a size.
| Material | Neoprene |
|---|---|
| Thickness | 2:4 |
| Colours | Black/orange |
| Fit | Men and women |
Pros
- Much easier to put on than a full wetsuit
- Keeps your core warm
Cons
- Not suitable for colder swims
This shorty wetsuit is ideal for summer when you want your arms and legs free but some extra warmth around the torso wouldn’t go amiss. It was a total joy to wear, according to our testers, who said they barely noticed they had it on as they moved through the water.
The fabric was thick enough to keep goosebumps at bay and the snug, figure-hugging fit meant there was no excess material to slow them down. Still, they enjoyed unrestricted movement around the arms and shoulders thanks to Orca’s clever infinity skin 2 technology, and there was no irritating chafing around the neck. Post-swim, the suit was a cinch to slip out of solo thanks to the generous zipper and it dried off quickly, too.
Everyone loved the bursts of colour beneath the arms and thought the design was extremely flattering. Look to one of our other options, like this Decathlon number, if you’re heading out in cold conditions, but if you just want some extra protection for your summertime swims or water sports sessions, this is your guy.
Shop now - women's
Key specs
| Material | Yamamoto 38 neoprene |
|---|---|
| Thickness | 2:3 |
| Colours | Black/orange |
| Fit | Women's |
Nabaiji Men’s Open Water Swimming Wetsuit 2/2mm
Pros
- Good insulation
- Excellent value
Cons
- Not suitable for triathletes
For fair-weather water babies who don’t want to spend over the odds on a techy suit, meet your new swimming companion.
It’s a great all-rounder, according to our testers, who found it was easy to pull on over their trunks and appreciated the decent range of motion it afforded them – it was flexible enough for most strokes, including breaststroke and butterfly. They rated the fit around the glutes, torso and chest but some found the wetsuit a bit too snug beneath the arms, making it tricky to run in. As such, we wouldn't recommend it for triathletes, but it’ll do the job nicely for all your casual swimming adventures.
Despite the modest price tag, testers were impressed with the overall quality of the suit, with many saying it had an expensive feel. They found it trapped heat well and offered enough insulation for the milder months. With a 2.5mm torso, however, it won’t keep you toasty enough during the freezing British winters.
Key specs
| Material | best wetsuits for open water swimming and triathlons |
|---|---|
| Thickness | 2.5:2 |
| Colours | Black/green |
| Fit | Men's |
Mountain Warehouse Women’s Full 2.5/2mm Wetsuit
Pros
- UV protection
- Take the plunge with these tested suits
Cons
- Best wetsuit overall
Another beginner-friendly option, this simple Mountain Warehouse style ticked several boxes for our testers. Unlike more techy suits that can be a bit of a fight to pull on, they had no issue slipping into this one – the fabric proved lightweight and supple, and the smooth easy-glide zip panel worked a treat. In the water, the stretchy neoprene allowed their arms and legs to move freely, and it successfully kept the cold at bay, even for short swims in near-zero temperatures.
With built-in UV protection of up to UPF 50+, it’s a great one to chuck in your suitcase for beach holidays. Plus, it has a rubber panel on the chest and tough, durable knee pads – useful additions if surfing, paddleboarding or river swimming are on the agenda. What’s more, it dried within 24 hours, so you can use it day after day.
Serious swimmers, look to one of our other options – panellists felt this one wasn’t high-tech enough for lengthy sessions – but it’s absolutely ideal for recreational swimming and water sports.
Key specs
| Material | Neoprene, polyester |
|---|---|
| Thickness | 2.5:2 |
| Colours | Updated: 29 May 2025 |
| Fit | Women's |
Orca Vitalis Breast Stroke Women Open Water Wetsuit
Pros
- Very flexible
- Not too difficult to take off post-swim
Cons
- Check the size guide before you buy
Like the Zone3 offering above, this good-looking style from the experts at Orca has been designed with breaststroke in mind. Unlike standard wetties, which can be on the stiff side, the Yamomoto neoprene is supremely stretchy and varies in thickness across the suit, allowing for total freedom of movement and a more powerful breaststroke position. Sure enough, our testers said thrashing through the stroke was a breeze, and it worked just as well for front crawl and freestyle, too.
Everyone loved the secure, silhouette-hugging fit and said it provided plenty of warmth, helping them stay in the water for longer. Despite the close-fitting design, it was easy enough to peel off after a swim, and the extra-long zipper meant they didn’t need a pal to help them shimmy out of it.
Panellists did report a strange smell when the suit was wet, and the sizing proved hit and miss – make sure you take your measurement before you buy – but those were our only gripes. All in all, an excellent choice for breaststroke aficionados.
Key specs
| Material | Yamamoto 38 neoprene |
|---|---|
| Thickness | 2:2.5 |
| Colours | Black |
| Fit | Women's and men's |
Pros
- Best wetsuit for warmth
- Aids buoyancy
Cons
- No high-vis features
A new and updated version of the much-loved Orca Sonar, the Athlex Flow is a favourite among intermediate triathletes. Our tester, who wore the suit while training for – and competing in – an Ironman-distance triathlon was impressed by the amount shoulder flexibility offered. He also enjoyed how the suit, which is made of flexible Yamamoto neoprene, aided buoyancy, allowing him to adopt a more streamlined body position in the water.
This wetsuit has a laser-cut design and is soft to the touch, and our tester found it very comfortable during long stints training in open water. The fit is also true to size.
Key specs
| Material | Yamamoto neoprene |
|---|---|
| Thickness | 2/3/4/5 |
| Fit | Men and women |
| Colours | Black/Silver |
How does a wetsuit work?
It’s vital you find a tight-fitting wetsuit because they keep you warm by acting as a second skin. When you submerge yourself in the sea (or your lake, pond or river of choice), a thin layer of water gets trapped between your skin and the neoprene. This is quickly warmed by your body heat, creating an insulating barrier between you and the icy currents.
But, be warned: cold water will rush into any baggy areas, causing a deeply unpleasant sensation known as flushing. It really is all about the fit.
Is a swimming wetsuit different?
Unlike 'normal' wetsuits, such as those you may use for surfing, wetsuits designed for wild swimming and triathlons are stretchier and extra flexible around the hips, knees and shoulders to help you swim more freely.
They are also more buoyant, helping you maintain the best body position in the water and therefore swim more efficiently.
Can you swim in a normal wetsuit?
While you can swim in a normal wetsuit, they are made from a different type of neoprene that's thicker and less comfortable and efficient to swim in.
Wetsuits designed for triathlon and open-water swimming also have a Super Composite Skin (SCS) coating, which is smooth and helps you to be more streamlined in the water.
Opting for an open-water specific swimming wetsuit will ensure you don't overheat and will make getting in those strokes easier.
Yanar was our former health and wellness tester.
Jodie is our Health and Fitness product tester. She runs tests on a wide variety of products, including gym leggings, walking boots, fitness trackers and more. Jodie has managed the testing for 577 products to date, including working with over 600 panellists.
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