This is our swimwear guide: the advice our swimwear experts give across the counter every day, written down in one place. Whether you're buying a first costume for lane swimming, a club suit for a teenager or something more supportive after years away from the pool, the same principles apply. Each section links to a more detailed post when you want to go further.

What will you be doing in the water?

The single most useful question in swimwear is what the suit is for. A costume that's perfect on holiday can be hopeless for 40 lengths before work, and a club training suit is overkill for splashing about with the kids.

Lane and fitness swimming

For regular lane swimming, you want a suit that stays in place through turns and push-offs and copes with chlorine week after week. For women, that usually means a one-piece training swimsuit with a secure back. For men, jammers or briefs. Our women's swimsuits are the place to start if you swim two or three times a week.

Club training

Club swimmers train often and hard, so durability matters most. Training kneesuits, one-pieces with athletic backs and training jammers are the staples. Racing suits are kept for galas.

Lessons and family swimming

Comfort and confidence come first. Children need a suit that doesn't slip, ride up or distract them, and adults returning to the water often prefer more coverage. Leisure styles and extra coverage suits work well here.

Holidays and the beach

Style has more room to breathe. Bikinis, tankinis, swim shorts and trunks are all fair game, though chlorine-resistant fabric still pays off if the hotel pool sees more of you than the sea.

How should a swimsuit fit?

Snugger than you think. Swimwear relaxes slightly when wet, so a suit that feels comfortably firm when dry is usually right. One that feels loose on dry land will gape, sag and let water in once you're swimming.

• Shoulders: straps should sit flat without digging in or slipping off when you swing your arms.
• Back: no gaping when you bend forward. If you can pinch a fold of fabric, it's too big.
• Legs: leg openings and grippers should lie flat without cutting in.
• Torso length: the suit shouldn't pull down on your shoulders or bag at the front.

Sizes vary a lot between brands, so treat your usual size as a starting point. Women's suits are usually sized by UK dress size or chest measurement, men's by waist, and children's by chest or age band. Our women's swimwear by UK dress size makes it easier to filter by what fits.

What fabric should swimwear be made of?

Fabric decides how long a suit lasts, especially in chlorine. Most swimwear is a blend of a hard-wearing fibre with some stretch.

• Chlorine-resistant polyester: the workhorse of training swimwear. Holds shape and colour well with frequent pool use, though it has less stretch.
• Elastane-rich blends: soft, stretchy and comfortable straight away, but tend to lose shape sooner with heavy chlorine use.
• Racing fabrics: thin, compressive and water-repellent. Brilliant on race day, not designed for daily training.

If you swim more than twice a week, we recommend chlorine-resistant fabric every time. Our post on chlorine-resistant swimwear explains the differences in more depth.

How should women choose swimwear?

Start with support and back style. A thin-strap, open-back suit gives freedom for training, while a wider-strap, closed-back suit gives more support and security. If you need extra bust support, look for built-in shelf bras, adjustable straps or suits designed for fuller busts.

Kneesuits have become popular with fitness swimmers as well as club squads, because the extra coverage on the thigh feels secure and stops riding up. For anyone who wants more coverage generally, higher necklines and longer legs are widely available in training-quality fabrics.

How should men choose swimwear?

Men have three main options for the pool: jammers, briefs and trunks or shorts. Jammers are the club standard, briefs suit swimmers who want freedom at the hip, and looser trunks or shorts are better for leisure than lengths, since they create drag. For club and lane swimming, start with our men's swimming jammers. Our men's swimwear covers every cut.

How should you choose children's swimwear?

Measure rather than buying by age. Children grow at very different rates and brands size differently, so a chest or waist measurement is far more reliable than an age label. Avoid buying a size up to grow into; a baggy suit slips, lets water in and knocks confidence in lessons.

Lessons call for comfortable, durable suits; club swimmers need training kneesuits, swimsuits or jammers; and young racers need a junior racing suit. Our girls swimwear runs from toddler to teen. Our boys swimwear covers the same range. For more, read our kids swimwear guide for parents.

THREE THINGS TO CHECK BEFORE YOU BUY

What else do you need with your swimwear?

Goggles that fit your face, a cap if you have long hair or swim in a club, and a bag that keeps wet kit away from dry clothes. Our guide to choosing swimming goggles picks up where this one leaves off. For caps, see our comparison of silicone, latex and fabric caps.

If you wear glasses, our explainer on prescription swimming goggles is worth a read. And to keep everything organised, see our comparison of swim bag types.

What if you need more support or coverage?

Plenty of swimmers want more from a suit than the standard cut gives. Fuller busts need wider straps, higher fronts and built-in support; our bust support swimwear is designed with that in mind. Swimmers who prefer more coverage for comfort, modesty or confidence can choose higher necklines, short sleeves and longer legs without giving up training-quality fabric.

Period swimwear is now a genuine option too, with absorbent built-in layers that let you swim through your period without a separate product. It's available for women and for girls, and it follows the same fit rules as any other suit: snug, secure and comfortable when you move.

Should you buy swimwear online or in store?

Both work, as long as you measure first. Online, use each brand's size guide rather than your clothing size, and read the product details for fabric and support. In store, do the bend-and-reach test and try two sizes if you're unsure.

Our shop in Dordon, near Tamworth, is open 8am to 4pm Monday to Friday, 8am to 3pm on Saturday and 10am to 2pm on Sunday, and our swimwear experts fit swimmers face to face every day. If you can't get to us, call 01827 330600 and we'll talk you through sizes over the phone.

How do you make swimwear last?

Rinse your suit in cool fresh water as soon as you can after every swim, gently squeeze out the water rather than wringing it, and dry it flat or hanging in the shade, away from radiators. Rotating two suits gives each one time to recover. Our swimwear care guide covers the details.

Written by a swimwear specialist at Allens Swimwear, 50 years of expert fitting. Updated 5 October 2026.