A guide for parents
What does a baby wear swimming?
The nappy rule that catches everyone out, whether you really need a wetsuit, and why swimming kit is some of the worst value you'll ever buy.
What's in here
- The double nappy rule
- Where to get them, and which sort
- Does your baby need a wetsuit?
- What to actually pack
- The rules nobody mentions until you break one
- Why swimming kit is worth buying used
First lesson, and you've got a swimming costume, a towel and a baby. That'll be a no, I'm afraid.
The double nappy rule
This is the one that catches everybody, and it's worth getting right before you turn up.
Most UK swim schools require two layers. A swim nappy underneath, disposable or reusable, and a neoprene over-nappy on top. Water Babies, Baby Squids and most others all ask for the same thing, and they will turn you away without it.
A swim nappy underneath
Disposable or reusable, whichever you prefer. It's the first line and it does most of the work.
A neoprene layer on top
The stretchy one with tight ribs round the waist and thighs. Usually an over-nappy, around £13 new, and Splash About's Happy Nappy is the best-known. It can also be a neoprene swimsuit or wetsuit with the ribs built in, which does both jobs at once.
Or one thing instead of two
Some neoprene swimsuits and wetsuits have the sealing ribs built in, so they count as the over-layer on their own. You still need the swim nappy underneath, but that's one less item to buy, lose, or forget.
Worth checking with your swim school first, since not all of them accept an all-in-one and the ones that do usually specify which.
Never a normal nappy
An everyday nappy in a pool soaks up several litres of water, weighs a ton, sags to their knees and can split open. Which is precisely the outcome the whole system exists to prevent.
Worth knowing what swim nappies actually do: they contain solids, not liquid. That's the whole job. Nobody expects otherwise and the pool chemistry handles the rest.
Where to get them, and which sort
There are two decisions and neither is complicated once somebody explains it.
| Disposable swim nappy | Reusable swim nappy | |
|---|---|---|
| Cost | Around 30p each | £6 to £10, used for months |
| Best for | Occasional swims, holidays | Weekly lessons |
| Works out cheaper if | You swim a handful of times | You go more than about twenty times |
| The catch | You must not forget one | Needs washing between lessons, so you want two |
Where to buy them. Supermarkets and Boots carry disposables. Reusables and neoprene over-nappies come from swim-specific brands, of which Splash About is the most widely stocked in the UK, and Amazon and the bigger baby shops carry the same. Your swim school will often sell them at the pool too, which is worth knowing on the day you've forgotten.
Sizing them. Go by weight rather than age, and snug rather than roomy. A gaping leg is the only way the thing fails, so it should feel firmer than a normal nappy does. Most brands publish a weight range on the packet.
And buy two reusables rather than one, because they need washing between lessons and a damp one from Tuesday is not a lesson-ready nappy on Thursday.
Does your baby need a wetsuit?
Depends on the pool, and it's genuinely worth asking rather than assuming.
| Pool temperature | What they need |
|---|---|
| Above 32°C | Usually just the nappy system. Most baby-specific pools sit here. |
| Around 30°C | Water Babies advise a wetsuit for under-twos at this temperature |
| Below 30°C | A wetsuit, and a warm one. Most public pools are around here. |
| Under three months, any pool | Ideally above 30°C, and thermal swimwear matters more the cooler it is |
The signs they're too cold are the ones you'd expect: shivering, blue lips, and going from happy to furious quite suddenly. Babies lose heat far faster than you do, which is why the lesson is thirty minutes rather than an hour.
The options, roughly in order of warmth. A wrap-style neoprene vest covers the body only and is easiest to get on. A shorty covers arms but not legs. A full fleece-lined suit covers everything and is what you want in a cool pool. And there's an all-in-one that combines the wetsuit and the over-nappy, so there's one less thing to lose.
What to actually pack
| For them | For you |
|---|---|
| Swim nappy plus neoprene over-nappy | Your normal swimming costume |
| Wetsuit, if the pool needs one | Towel, and a second one |
| Spare swim nappy | A change of clothes for after |
| Towel, ideally hooded | Something to eat afterwards. They'll be starving. |
| Warm hat for the way home | A small roll-up changing mat |
| Normal nappy for after | A bag for everything wet |
The hat is the one people skip and then regret. Little heads lose heat quickly and a wet baby going out into a car park in February is colder than you'd think.
The rules nobody mentions until you break one
No swimming for 48 hours after any tummy upset. Not a suggestion. Swim nappies hold solids and nothing else, so this is the rule that protects everybody.
If there's a leak, tell the teacher immediately. Nobody will be cross with you. But the pool has to close for a few hours, your class ends, and so do the ones after yours. Which is why the double nappy exists and why they check.
And if there's eczema, Water Babies suggest a barrier cream on the affected areas before getting in, then a sun suit over the top. Worth asking your own teacher rather than assuming, since they'll have seen it plenty of times.
Why swimming kit is worth buying used
Here's the maths, and it's not pretty.
A wetsuit costs around forty pounds and gets worn once a week. A term is a dozen lessons, and by the next one they've gone up a size. The neoprene isn't remotely worn out; they've simply grown.
Which makes swimming kit close to a perfect thing to buy secondhand. It's chlorine-resistant, it holds its shape, and the reason it's being sold is never that it failed.
The one to buy new is the under-nappy, for obvious reasons. The wetsuit, the over-nappy and the sun suits are all fine used, provided the ribs on the neoprene still have their stretch. Where to look is here.
We turned up to the first lesson with a swim nappy and no neoprene one and were very politely sent to sit at the side. Nobody had said, and I'd read the whole email twice.
🌱 While you're here
A wetsuit outgrown after two terms is worth something to the family whose baby starts lessons next month, and nothing at all in your cupboard.
Swapaboo is a clothes swap. What they've grown out of pays for their next size, so the clothes themselves cost you nothing. You just pay to have them moved. Swimwear and wetsuits included.
Everything's checked and graded before it lists, so it's never a mystery bag, and you pick every piece yourself.
We're opening a few families at a time. Pop your email in and we'll let you know when there's a place.
Common questions
What does a baby wear swimming?
Most UK swim schools require a double nappy system: a swim nappy, disposable or reusable, with a neoprene over-nappy on top. A wetsuit is added if the pool is below about 32 degrees. Ordinary nappies must never be worn in a pool, since they absorb water, become extremely heavy and can split.
What is a double nappy system for swimming?
Two layers: a swim nappy underneath and a neoprene over-nappy on top. The over-nappy has tight ribs at the waist and thighs which create a seal. Water Babies, Baby Squids and most other UK swim schools require it, and lessons are usually refused without one.
Does my baby need a wetsuit for swimming lessons?
It depends on the pool temperature. Above about 32 degrees, the nappy system alone is usually enough. Water Babies advise a wetsuit for children under two in a pool at 30 degrees, and below that a wetsuit is generally needed. Babies lose heat much faster than adults, so shivering, blue lips or sudden distress mean it is time to get out.
Can a baby wear a normal nappy in a swimming pool?
No. An ordinary nappy absorbs several litres of water, becomes very heavy, sags and can split open in the pool. Swim nappies are designed not to absorb water and to contain solids, which is the specific job that matters.
Can you swim after a tummy upset?
Not for at least 48 hours after the last episode. Swim nappies contain solids but not liquid, so this rule protects everyone using the pool. If a leak does occur, tell the teacher straight away: the pool will usually need to close for several hours and the following classes are cancelled.
Where can I buy swim nappies?
Disposable swim nappies are stocked by supermarkets and Boots. Reusable ones and neoprene over-nappies come from swim-specific brands, with Splash About the most widely stocked in the UK, and are also sold by Amazon and larger baby shops. Many swim schools sell them poolside, which is useful on the day you have forgotten one.
Are disposable or reusable swim nappies better?
Disposables cost around 30p each and suit occasional swims. Reusables cost roughly £6 to £10 and work out cheaper beyond about twenty swims, so they suit weekly lessons. Buy two reusables rather than one, since they need washing between sessions. Size by weight rather than age, and fit them snugly, because a gaping leg is how they fail.
Can a neoprene swimsuit replace the over-nappy?
Sometimes. Some neoprene swimsuits and wetsuits have the sealing ribs built in and count as the over-layer on their own, with a swim nappy still worn underneath. Not every swim school accepts an all-in-one, so it is worth checking which they permit before buying.
Can you buy baby swimming kit secondhand?
Yes, apart from the under-nappy. Wetsuits, neoprene over-nappies and sun suits are all suitable secondhand, since they are chlorine-resistant, hold their shape and are outgrown long before they wear out. Check that the ribs on any neoprene item still have their stretch.