Period Swimwear: The Complete Guide for Every Swimmer

Periods stop a lot of girls and women swimming, and they should not have to. This guide explains what period swimwear is, how it actually works in water, and how to choose and size it across every stage, from a junior just starting her periods to an adult training or racing. It covers the honest limits of what the garment does, when to pair it with a tampon or cup, and how to look after it so it keeps performing. Where it helps, we point to the specific collections we stock.

What is period swimwear?

Period swimwear, sometimes called period-proof swimwear, is a swimsuit or swim brief with an absorbent, leak-resistant lining built into the gusset. It is designed to hold light menstrual flow while a swimmer is in the water and to resist leaks getting out, so a girl or woman can swim during her period without a pad, which does not work once wet.

It looks and fits like ordinary swimwear from the outside. The difference is a discreet multi-layer lining that most people cannot see or feel. Period swimwear is not a medical device and it does not replace all other protection on heavier days, but for many swimmers it is the piece of kit that lets them keep training through the month.

How does period swimwear work?

The lining uses bonded layers that each do a job. A top layer sits against the skin and lets flow pass through, an absorbent core holds it, and a leak-resistant barrier reduces what escapes into the water. Because the garment is built for swimming, the core is slimmer than the one in period pants made for dry-land wear, so capacity is lighter by design.

Water pressure also helps. While a swimmer is submerged, flow is naturally very light, which is part of why period swimwear performs well in the pool. The honest picture is this: it is well suited to light and the start or end of a period, and for heavier days our swimwear experts advise pairing it with a tampon or menstrual cup for confidence. We do not quote capacities or wear times, because they vary by product and by person, and the right answer is always to choose protection for the day you are having.

Period swimwear for juniors: a guide for swim parents

For a girl who has just started her periods, the first few in the water can feel like a reason to stop swimming altogether. A tampon can feel like a big step for a young swimmer who is not ready for one, and a pad is no use in the pool. Period swimwear gives her a familiar, invisible option that looks exactly like her normal costume, which is often all it takes for her to carry on at club.

Fit is what matters most here. A junior period suit needs to sit snugly at the legs and gusset without digging in, because a secure fit is what keeps it working and keeps her confident on the blocks or at the lane end. Buy to her current measurements rather than sizing up for growing room, since a loose gusset is the main cause of leaks. Our swimwear experts talk parents through this every week, by phone, email or in person at our Dordon store, and will happily help you measure at home.

Keep the conversation practical and matter of fact. A young swimmer takes her cue from how the adult around her treats it, and framing period swimwear as just another piece of kit, like goggles or a cap, takes the worry out of it. Our girls' period-proof swimwear is chosen with exactly this age group in mind.

Teens and adults: training and competition

For older teens and adults, the question is usually about training load and racing rather than first periods. A swimmer doing five or six sessions a week wants something she can put on without a second thought, that holds up through a hard set and does not distract her mid-lane. Period swimwear in a training style does that job, worn the way she would wear any other costume, with a tampon or cup added on heavier days.

Competition is a separate consideration. Dedicated period swimwear is training and leisure kit, not a World Aquatics (WA) approved race suit, so for a licensed gala a swimmer still races in her approved suit. On a heavier race day many swimmers use an internal option such as a tampon or cup under the race suit, and plan warm-up and marshalling around it. If you are unsure how to combine period protection with competition kit, our swimwear experts can talk it through.

Styles, brands and what to look for

Period swimwear comes in the same shapes as ordinary swimwear, so a swimmer can keep the style she already likes. The main choice is between a one-piece and a two-piece, and between a leisure cut and a training cut. We stock period swimwear from Funkita and Speedo, both brands we are an authorised UK stockist for, which means genuine product and full manufacturer backing.

Three things to look for in a period swimsuit

How to get the fit right

Getting the size right is the difference between period swimwear a swimmer trusts and one she abandons after a single leak. Order from the brand's own size chart using measurements, not age or dress size, since each brand cuts differently. Take a tape measure around the chest, waist and hips and compare those figures to the chart on the product page.

The gusset and leg openings deserve particular attention. They should sit snug and flat with no gaping, because that seal is what keeps flow contained. For a junior, resist the urge to size up for growing room; a suit that is slightly too big is a suit that leaks. If a swimmer falls between two sizes, or you are buying for a growing teen, our swimwear experts will help you choose before you order, and if it is not right when it arrives we offer free UK returns within 28 days.

Caring for period swimwear

Period swimwear lasts longest when it is looked after like the technical garment it is. Rinse it in cold water as soon as possible after swimming, before the lining dries, then wash it cool and let it drip dry away from direct heat and radiators. Avoid the washing machine on a hot cycle, the tumble dryer, fabric softener and bleach, all of which break down both the elastane and the absorbent layers.

A cold rinse straight after a session matters most, and it is the one step swimmers most often skip. Chlorine and warmth are what wear swimwear out, so treating period swimwear gently keeps both its fit and its lining working through regular use. Cared for this way, it stays reliable season after season.

Written by a swimwear specialist at Allens Swimwear, 50 years of expert fitting.