Kids Swimwear Guide For Parents
We've been kitting out children for swimming since 1976, from babies' first splash sessions to junior internationals. Parents ask us the same handful of questions every week: what size, which style, which fabric and when to upgrade. This kids swimwear guide answers all of them, and it's the hub for our Kids & Junior Swimming posts, so follow the links for more detail.
How do you size children's swimwear?
By measurement, not age. Two eight-year-olds can be several sizes apart, and every brand's age bands are slightly different. A chest measurement for girls, a waist measurement for boys and a torso length for one-piece suits will get you far closer to the right size than an age label.
Our step-by-step guide on how to measure your child for swimwear shows exactly where to measure and how to read a brand's size chart.
The mistake: Buying a size up so the suit will last another year.
What happens: The suit gapes at the back and slips off the shoulders, water floods in during lessons, and your child spends the session tugging at it instead of listening to the teacher.
How to avoid it: Buy the size that fits now. Swimwear relaxes slightly when wet, so a suit that's snug on dry land is usually right.
Which style of swimwear suits children best?
Which Style for Which Swimmer?
| Activity | Girls | Boys |
|---|---|---|
| Toddler and baby swimming | Swimsuit with swim nappy where the pool requires it | Trunks or swim shorts with swim nappy where required |
| Lessons | Comfortable one-piece swimsuit or kneesuit | Jammers or trunks |
| Club training | Training swimsuit or kneesuit in chlorine-resistant fabric | Training jammers in chlorine-resistant fabric |
| Galas | Junior racing kneesuit | Junior racing jammers |
| Holidays | Swimsuits, tankinis, sun suits | Swim shorts, trunks, sun tops |
For lessons, comfort and confidence come first. A one-piece that doesn't ride up and stays on the shoulders is ideal for girls; jammers or trunks work well for boys. Avoid loose board shorts for lessons, as they drag in the water and make learning harder.
Our girls swimwear runs from toddler sizes to teens. Our boys swimwear covers the same span.
Which fabrics last longest for children?
Children who swim every week are tough on swimwear. Chlorine-resistant polyester fabrics hold their shape and colour far longer than soft, stretchy fashion fabrics, so they're the best value for lessons and club training. Save softer holiday swimwear for the beach.
Rinsing the suit in cool fresh water after every swim, and drying it away from radiators, makes a big difference too. Our swimwear care guide has more tips.
Which goggles should children wear?
Goggles that fit their face. Small children need small frames and soft seals, and older children usually move into junior versions of adult goggles. A good-fitting pair seals without being pulled tight, which means no leaks and no red rings round the eyes.
Our junior swimming goggles suit school-age swimmers. For toddlers and pre-schoolers, we have goggles for ages 0 to 6.
What do children need for a swimming club?
Clubs usually ask for a training swimsuit or jammers, goggles, a silicone cap (often in club colours), and a bag big enough for a kickboard, pull buoy and fins. Our guide to your child's first swimming club covers the full list.
THREE STAGES OF KIDS SWIMWEAR
THREE STAGES OF KIDS SWIMWEARLearning
LearningComfortable suits and well-fitting goggles that build confidence. Comfort beats everything at this stage.
Club training
Club trainingChlorine-resistant training suits, a silicone cap and basic training aids. Durability matters most.
Racing
RacingA junior racing suit for galas, kept separate from training kit. Upgrade when the coach says so.
When should children move to racing swimwear?
When they start racing at galas, a junior racing suit is the natural next step. These are cut for growing bodies, easier to get on than adult race suits and made in more durable fabrics. For girls, our junior racing kneesuits are a good place to start. For boys, look at our junior racing jammers.
Before buying anything more advanced, check the rules. Some meets restrict technical race suits for younger swimmers, and our guide to World Aquatics (WA) approved swimwear explains what to look for.
How do you know when your child has outgrown their swimwear?
Watch for straps digging into the shoulders, the suit pulling down at the front, leg openings cutting in, or your child constantly adjusting it. Thinning, see-through patches and baggy seats are signs of chlorine wear rather than growth, and mean it's time for a new suit either way.
Measure again every few months during growth spurts. Our swimwear experts are happy to check sizes if you're unsure.
Why Buy Kids Swimwear From Allens Swimwear
Family-run since 1976, we've kitted out generations of young swimmers, from first lessons to junior internationals.
Written by a swimwear specialist at Allens Swimwear, 50 years of expert fitting. Updated 5 October 2026.
Frequently Asked Questions
How do I know what size swimsuit to buy my child?
Measure your child's chest, waist and hips, and compare them to the brand's size chart rather than relying on the age label. Swimwear should feel snug when dry, as it relaxes slightly when wet.
Should I buy my child's swimwear a size bigger?
We don't recommend it. A suit that's too big slips, lets water in and distracts children during lessons. Buy the size that fits now.
What swimwear is best for swimming lessons?
A comfortable one-piece swimsuit or kneesuit for girls, and jammers or trunks for boys, in chlorine-resistant fabric. Avoid loose board shorts, which drag in the water.
Do children need chlorine-resistant swimwear?
If they swim every week, yes. Chlorine-resistant fabrics hold their shape and colour far longer, which makes them better value for lessons and club training.
When does a child need a racing suit?
When they start competing at galas. A junior racing suit is the right first step; more advanced race suits can wait until the coach recommends one.