Can You Swim in Merino Wool Shorts?

Yes. Merino wool handles being wet better than most people expect: it doesn't go clammy against your skin, it dries fast, and it won't hold onto the smell of a swim the way synthetic fabrics do. You can jump in the ocean, a lake or a pool in merino shorts without a second thought.

The part worth knowing before you make it a daily habit is what repeated chlorine or saltwater exposure does to the fibre over months, not what happens on one swim. That's the difference between "yes, swim in these" and "yes, but rinse them after."

What actually happens when merino gets wet

Merino fibre absorbs moisture into its core rather than sitting on the surface the way polyester does. Wool can take on up to 30% of its own weight in moisture before it starts to feel wet, according to Campaign for Wool, the Woolmark-backed industry body. That's why a soaked merino short still feels manageable rather than heavy and sticking to your legs.

It also breathes while wet. The fibre keeps working through its usual moisture cycle, pulling water through and releasing it as vapour, so you're not walking around in a plastic bag full of trapped sweat and lake water. Combined with UPF properties from the keratin structure of the fibre itself, it's a genuinely reasonable thing to wear in and out of the water all day.

Saltwater is fine. Just rinse it after.

A swim in the ocean won't hurt a merino short. What will, over enough repetitions, is never rinsing the salt back out. Salt left in the fibre after it dries can degrade wool over time, which is why brands making merino swimwear tell you to give it a quick rinse in fresh water once you're done, then hang it to dry.

One swim and a rinse changes nothing. A season of ocean swims with the salt left to dry in every time will shorten how long any wool garment lasts. It's a thirty second habit, not a chore.

Chlorine is the one to actually watch

Chlorine is harder on wool than saltwater. Used occasionally in a backyard or hotel pool, it's a non issue. Used daily over months, chlorine gradually breaks down the protein structure in the fibre. You'll see it as colour fade and thinning fabric before anything dramatic happens.

The fix is the same as with saltwater: rinse in fresh water straight after, skip sitting in a hot tub afterward, and don't let chlorinated water dry into the fabric repeatedly. If your day includes one pool dip, wear the shorts without a second thought. If your routine is laps most mornings, that's a different use case, and it's worth being honest about that below.

How fast does it actually dry

Faster than cotton, and not far off some synthetics, though the exact number depends on the weave and weight of the fabric. Vilebrequin's merino swim shorts, woven at a much higher density specifically for swimwear, are reported to dry in five to seven minutes. A knit merino walkshort is built differently, for all day wear rather than a beach lap session, so expect it to sit somewhere between that and a heavier cotton short. [ZACK: confirm approximate dry time for the Walkshort after full submersion, a simple rinse and hang timing test would do]

Either way, you're not waiting around in wet shorts for an hour the way you would in cotton chino shorts, and you're not stuck with the permanent synthetic smell that comes from polyester boardshorts that never fully dry between wears.

Merino swimwear is already a category, just not in walkshorts

Woolmark has worked with Vilebrequin on merino swim shorts. Sheep Inc launched merino swimwear in 2025, positioned as the first swimwear made entirely from natural materials rather than recycled plastic. None of it is walkshorts built to go from a coffee run to a swim to dinner. That gap, a single pair of shorts that works for all of it rather than a dedicated swim-only piece, is exactly what we're building toward with the natural fibre boardshort still in development. Read more on the natural fibre boardshort page if that's the gap you've been waiting on too.

The honest limits

Two things to know before you treat merino shorts as your swim gear full time.

Daily lap swimmers in a chlorinated pool will get more life out of dedicated swimwear built for constant chlorine exposure than out of a wool short worn the same way. Competitive swimmers wear polyester and PBT blends for exactly this reason: those fibres don't break down under daily chlorine the way wool eventually will.

Synthetic swim trunks also dry a touch faster in direct sun and heat, because the fibre itself holds close to zero water. That's a real advantage for someone doing multiple swims back to back in a single afternoon. It doesn't change much for someone swimming once and getting on with the rest of the day, which is the more common way these shorts actually get worn.

What this means for you

Swim in them. Ocean, lake, pool, whatever's in front of you. Rinse with fresh water afterward if it was salt or chlorine, hang them to dry, and you're set for years of normal use. Save the daily chlorinated laps for dedicated swimwear.

FAQs

Can you swim in merino wool shorts in the ocean?

Yes. A swim in saltwater doesn't damage merino. Rinse the shorts in fresh water afterward so salt doesn't sit in the fibre and dry there repeatedly.

Does merino wool get heavy when it's wet?

It gets noticeably damp but not as heavy as cotton. Merino holds moisture inside the fibre rather than on the surface, and it can take on close to a third of its own weight before it feels properly wet.

Can you swim in merino wool in a chlorinated pool?

Yes, occasionally, without issue. Daily lap swimming in a chlorinated pool over months will fade and thin wool faster than dedicated swimwear built for constant chlorine exposure. Rinse in fresh water after each swim.

Do you need to wash merino shorts every time you swim in them?

No. A fresh water rinse and an air dry is enough after most swims. Save an actual wash for when they're dirty or start to smell, following the same care routine as any other merino garment.

Sources

• Campaign for Wool (Woolmark-backed): wool moisture absorption before feeling wet
• Branwyn: merino wool performance and care for water sports
• Merino Country: chlorine effects on wool and post-swim care
• Woolmark: Vilebrequin merino swim short drying performance
• Dezeen: Sheep Inc merino swimwear launch, 2025

Most shorts are made from plastic. These aren't. See the MARINE|O Merino Wool Walkshort →