Merino wool swimwear is back — and it's changing the way we think about sustainable swimwear. Here's everything you need to know.
Can you actually swim in merino wool?
Yes — and this is the question almost everyone asks first. Merino wool swimwear is nothing like the itchy, heavy wool you're thinking of. Merino fibres are ultra-fine, which means they're soft against skin, quick to dry, and surprisingly comfortable in water.
At swimm, our pieces are designed specifically for water — whether that's laps in the pool, a dip at the beach, or a soak in a hot spring, spa or sauna.
Did you know swimwear was originally made from wool?
Before synthetic fibres existed, wool was the swimwear fabric of choice. In the late 1800s and early 1900s, swimmers wore full-length wool bathing suits. Wool was used because it was the best natural option available — it handled water, regulated temperature, and held its shape better than cotton.
When nylon and polyester arrived in the mid-20th century, the industry shifted almost entirely to synthetics because they were cheaper to produce and faster to dry. Wool was left behind.
But synthetics came with a cost nobody was counting at the time — microplastic pollution, petroleum dependence, and garments designed to be replaced every season rather than last for years.
What makes merino wool different from regular wool?
Regular wool fibres are coarse and can feel scratchy. Merino wool comes from Merino sheep and has a much finer fibre diameter — typically under 20 microns — which is what makes it soft enough to wear directly against skin.
It's also naturally:
- Temperature-regulating — warm when you're cold, cool when you're warm
- Odour-resistant — naturally antimicrobial, so it stays fresh longer
- Moisture-wicking — moves moisture away from the skin rather than holding it
Why isn't all merino wool swimwear 100% wool?
100% wool is too heavy for swimwear and lacks the stretch needed for full movement in water. Swimm uses a 96% merino wool to 4% elastane blend — the small addition of elastane gives the fabric four-way stretch while preserving everything that makes merino exceptional: temperature regulation, odour resistance, and a soft, natural feel against skin.
Does merino wool swimwear offer UV protection?
Yes — merino wool naturally provides UPF 20+ sun protection. Unlike synthetic fabrics that rely on chemical treatments for UV resistance, merino's natural fibre structure absorbs and blocks UV radiation, making it a genuinely protective choice for time spent outdoors in the water.
Is merino wool swimwear sustainable?
This is one of the most searched questions in the sustainable fashion space — and the answer is yes, with nuance.
Merino wool is a natural, renewable fibre that biodegrades at end of life, unlike synthetic swimwear (nylon, polyester, spandex) which sheds microplastics into waterways every time it's washed.
Is merino wool swimwear chlorine & salt resistant?
Merino wool has natural resistance to chlorine and salt water compared to synthetic fibres, which can degrade quickly in heavily chlorinated pools or the ocean. That said, we recommend rinsing your swimwear with fresh water after every use to extend its life — the same as you would with any quality piece.