How to choose a shoulder season suit
Core warmth, swim-specific design and flexibility for a natural, unrestricted stroke: Olivier Wallien, from Dutch water ware brand WALLIEN, explains what to look for in a shoulder season suit
What kind of outdoor swimmer suits a spring suit?
A spring suit is ideal for the swimmer who wants a natural, unrestricted stroke while keeping the core warm. It’s the perfect in-between layer: it extends your skins season at both ends, spring and autumn, before conditions call for a full suit – without the bulk or restriction of one. If you swim front crawl and value shoulder freedom, but still want protection through the torso, a spring suit is built for you.
What fit should we look for?
Fit is everything with a spring suit – it should feel like a second skin: snug, secure and moulded to your body. Check that there are no gaps at the neck, lower back or under the arms, because any gap lets cold water flush through, and that the wrists and ankles sit close without biting. You’re looking for a suit with no big folds of loose material (small wrinkles are fine) that still lets you rotate your shoulders and reach overhead freely. Natural rubber (Yulex) gives a little over a few sessions, so a new suit should feel properly snug from the start. A pattern shaped to the female form rather than a scaled-down men’s suit, makes a real difference to comfort and warmth.
What thickness would you recommend?
As a general guide, a 1.5-2mm spring suit is well suited to water of roughly 18–22°C – classic shoulder-season swimming on brighter days. Once you drop below around 18°C most swimmers will want to move toward a 3/2mm full suit, and above ~22°C many are happy in skins or a costume. The WALLIEN Horizonia springsuit runs at 1.5mm, and the new Boyleg at 2mm, which adds extra warmth and coverage through the hips and thighs for cooler sessions.
How are shoulder season suits constructed to balance warmth and flexibility?
This is exactly what wetsuit thickness notation describes. A figure like ‘3/2mm’ means 3mm over the core, where warmth matters most, and 2mm through the arms and legs, where mobility matters most – warmth where you need it, flexibility where you move. A spring suit is thin all over by design, so the stroke stays free, but the same logic tells you what to check: how light and stretchy is the suit around the shoulders and armpits? It’s also worth looking at the seams – glued and blind-stitched (GBS) seams are the gold standard for keeping water out while staying flexible and durable, whereas simple flatlock seams can let a little water through.
What should we look for in terms of zips?
A pull-on, zip-free design gives the most flexibility with nothing to dig in, while a zip is quicker to get in and out.
What benefits does Yulex have?
Yulex is a natural rubber, harvested from FSC-certified plant sources, rather than the petroleum- or limestone-based neoprene used in most wetsuits. It performs comparably to premium limestone neoprene on warmth and stretch, but with around an 80% lower CO2 footprint in the raw material – so it’s genuinely the most responsible option available rather than a compromise.
Is there a difference between a surf-specific and a swim-specific cut?
Yes, and it matters. Surf suits tend to prioritise durability and warmth for sitting and waiting between waves: more coverage, higher necklines, sometimes heavier seams. A swim-specific cut prioritises shoulder mobility and a streamlined, low-bulk fit, so nothing interrupts your stroke or creates drag. WALLIEN is designed by water women, for water women, so our suits are cut for movement in the water first.
How should you look after a shoulder season suit?
To make your spring suit last, rinse it in cold, fresh water after every session, dry out of direct sunlight, never machine-wash, and store on a proper wetsuit hanger. Look after a natural-rubber suit and it will serve you for years, which is the more sustainable approach, too.
Browse WALLIEN spring suits here.
WALLIEN Horizonia Yulex® Springsuit Boyleg
£189
For those who prefer a little more coverage, this boyleg suit by Dutch brand WALLIEN fits like a second skin. It utilises exceptionally stretchy 2mm natural rubber that contours beautifully to the body. The back zip requires a little bit of shoulder wiggling to get on and off, but once on, the smooth linings feel entirely seamless and streamlined. Glued and blind-stitched seams completely block cold water from flushing into the suit. JT
SCALES Twinset Crop and Briefs
£155 (top) + £93 (briefs)
If you find traditional wetsuits too restrictive, these premium neoprene crop and briefs separates offer a beautifully designed, stylish solution. Engineered for high-intensity ocean activities like surfing, wakeboarding, and open-water swimming, the twinset sits completely flat against the skin and stays securely anchored as you move. The insulated neoprene targets warmth directly to your core, for minimal drag, while the elegant high neck shields your chest from any wind chill. JT
CHILLY SWIM The Tentaliser
£159.99
At 2mm, this new Chilly Swim suit with cheeky tentacle design offers a flex Lycra lining and front-opening zip. It’s a variation on a similar suit offered by the brand but comes in a bigger size range and the added zip ensures it is much easier to get on and off. This is a great example of a brand responding to customer feedback and improving an already brilliant suit. What I like is the cut and shape, which feels both figure-hugging and practical, leaving shoulders and legs bare while keeping the core warm. It is lovely to swim in and the new design is fun and comes in two colorways. EF
FINISTERRE Kaia 2mm Yulex® Pant and Long-Sleeve Top
£60 (pants) + £120 (top)
These Yulex shorts and long-sleeve zip up top make such a versatile set, which you can layer on top of swimwear in a variety of ways as you move through the seasons. The 2mm natural rubber is ideal for shoulder seasons (everyone is different but this feels comfortable to me in temps ranging 15ºC-21ºC). The top has racer-back shoulder seams, seamless underarms and laser-cut raw edge cuffs to eliminate any kind of friction or rubbing. The Yulex should feel snug when you first put it on; it loosens up a touch in the water. JT
ZONE3 Ti+ Long Sleeve Thermal High Neck Swimsuit
£85
There is some clever technology behind this high-performance swimsuit from Zone3. While traditional swimwear fabric lets your body’s infrared heat escape, the microscopic titanium metal particles woven into the fabric lining of the Ti+ suit act like a thermal mirror, reflecting your own body heat straight back toward your skin. As it’s not neoprene, there’s very little shoulder resistance, allowing for an entirely natural, unhindered stroke with minimal drag. You really do notice the difference, too – I found I could stay in the water much longer than in a standard swimsuit thanks to the core warmth. JT
SCALES Neoflex
£240
With its subtle cap sleeves, gently compressive contoured panels, and understated earth-toned colours, this Scales one-piece suit just looks elegant. I particularly liked the high collar, which kept the back of my neck lovely and warm. It’s not just about looks, though; made with 2mm premium Japanese limestone-based rubber, the Scales Neoflex provides a decent amount of core warmth, while a hydrodynamic smoothskin finish minimises drag. This is a suit you can swim unhindered in and feel good in. JT
ZONE3 Yulex® Sleeveless Swimsuit
£110
The sleeveless racerback cut of this Yulex swimsuit ensures there’s zero restriction around your shoulders and arms, so you can swim unhindered. Meanwhile, the 1.5mm natural rubber provides a good degree of core warmth; it has allowed me to have a few decent swims in 18-20ºC water. It obviously doesn’t give the buoyancy of a full wetsuit, and it’s not coated so there are more hydrodynamic spring suits out there if speed is your goal, but it’s soft, flexible and comfortable and a solid choice for transitional months. JT
All products were chosen independently by our editorial team. This review contains affiliate links and we may receive a commission for purchases made. Click here to subscribe to the magazine. Read more Outdoor Swimmer gear reviews.
Jo Tinsley
Jo is the Gear Editor for Outdoor Swimmer and also writes news and features for the website. A keen open water swimmer and long-distance walker, she loves seeking out lakes and lidos close to her home in the Mendip Hills, Somerset. She is the author of The Slow Traveller, editor and founder of independent magazine, Ernest, and has previously tested outdoor clothing and kit for BBC Countryfile Magazine, BBC Focus and Ernest Journal.
