Which swimwear materials are actually sustainable?

These days, swimwear can be made from recycled fishing nets, plastic bottles, wood pulp or even beans! But which materials are truly sustainable, while providing the performance we need in the water?

The one made from fishing nets

Recycled synthetics are the most common sustainable choice because they provide the necessary stretch, chlorine resistance and durability of traditional swimwear without relying on virgin petroleum. ECONYL® is a 100% regenerated nylon fibre made from waste such as discarded fishing nets, fabric scraps and old carpets. It performs identically to virgin nylon and can be recycled infinitely.

Independent Cornish brand Made of Water chose to use ECONYL® because of its strong environmental credentials. “As a brand rooted in the ocean, it felt important to use a material that actively helps remove waste from marine environments while also producing a premium fabric that lasts,” says Amanda Charles, founder of Made of Water.

ECONYL® performs exceptionally well for swimwear. It’s durable, supportive and holds its shape over time, with excellent stretch and recovery. It’s also resistant to chlorine, saltwater and sun creams, which makes it ideal for regular open water swimmers. “The longevity of the fabric is really important to us, we want our pieces to last season after season,” says Amanda.

The (other) one made from fishing nets

NetPlus® is another material made with 100% from post-consumer recycled fishing nets, but the brand behind it, Bureo, emphasises a fully traceable supply chain from the specific fishing community to the final product. “Not all recycling is equal,” says Greg Swienton of Bureo. “Through the NetPlus® recycling program, discarded nets are sourced directly from fishing communities before they can end up in the environment. The material is 100% traceable, meaning the entire process from collection through recycling is third-party audited and certified for material traceability.”

Outdoor brand Passenger chose NetPlus® in their men’s boardshorts as they wanted a fabric that was quick-drying, durable and more sustainable. “The fabric has a beautiful texture and a nice matte finish,” says Hannah Jamieson, menswear designer at Passenger. “We love the story about turning fishing nets into fabric, so using NetPlus® in our boardshorts instead of virgin plastic was a no-brainer, fully aligned to the Passenger ethos.”

The one made from plastic bottles

Another common choice is REPREVE®, a leading brand of recycled performance fibre made primarily from post-consumer plastic bottles (PET) at high risk of entering the ocean (collected from coastal areas within 50km of waterways that lack formal waste management).

Performance-wise, REPREVE® is known for its durability, moisture management and thermal regulation. It’s a great choice for swimwear because it matches or even exceeds the quality of traditional ‘virgin’ polyester while being more sustainable. It is engineered to withstand the harsh conditions of aquatic environments, including prolonged exposure to sun, salt and pool chemicals. It’s also quick-drying, retains its shape and feels soft to touch. Brands that use REPREVE® include Finisterre, Batoko and (in limited products) Speedo.

The one made from wood pulp

Lyocell, commonly known by the brand name TENCEL™, is a semi-synthetic fibre made from dissolved wood pulp, typically from fast-growing eucalyptus, beech or birch trees. It’s prized for being a sustainable, high-performance alternative to both natural cotton and fully synthetic polyester.

“Most conventional swimwear is mainly made from synthetic fibres such as nylon or polyester. While these materials are great for swimming and chlorinated pools, they are essentially plastic-based textiles that were never meant to be worn in hot environments,” says Victoria Arnhold, founder of Saade, which recently launched the first sauna swimsuit. “Regular swimwear isn’t breathable, can trap heat and moisture and may shed microplastic particles onto the skin when worn in sauna; it’s basically sweating in plastic. But natural fabrics, such as cotton or hemp, are also not ideal for swimwear as they absorb a lot of water and dry slowly, which can trap bacteria.”

In swimwear, Lyocell offers a “best of both worlds” solution – a natural fibre base with technical performance that works both in the heat and in the water. It’s breathable, naturally absorbs and releases moisture efficiently, dries quickly and feels soft and smooth against your skin.

The one made from natural fibres

Saying that, natural fibres like hemp and organic cotton do also provide a plastic-free, biodegradable alternative, but to make sure they perform well as swimwear, you have to use the material cleverly. UK brand Swim Good uses a innovative 3D loop weaving method with 100% OEKO-TEX cotton to create a cotton fabric that promises to be breathable, stretchy and even quick-drying. Their first collection sold out online, so we haven’t tried it, but they’re one brand to watch.

The one made from beans

How about a swimsuit made from beans? Bio-based Polyamide, known as Evo®, is a yarn derived from castor beans, offering a renewable alternative to fossil-fuelbased nylon. “Luxury oceanwear” brand SLO active uses Evo® in their range of swimwear, promising a supportive fourway stretch fabric that’s lightweight, breathable, moisture wicking and chlorine resistant with a UPF 50+ rating.