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Page Reviewed 01/24/23

Your Guide to Swimming Diapers

Swim diapers are a must for any child who isn’t potty trained and wants to enjoy a dip in the pool, baby and toddler swim classes, or the sea.

Our in depth guide to swim diapers will help you avoid the inconvenience and embarrassment of your child having an accident in the water.

This guide features:

  • Disposable and reusable swim diapers comparison chart

  • Swim diaper size guide

  • 5 Top tips for using a swim diaper

  • Step-by-step guide to using a reusable swim diaper

  • How many swim diaper do I need?

  • Swim diaper FAQs

Disposable and reusable swim diapers comparison chart

  • A disposable swim diaper looks like a regular diaper and is worn once and thrown away
  • A reusable swim diaper looks like a regular pair of swimming shorts or forms part of a swimsuit and can be worn multiple times
  Reusable Swim Diaper Disposable Swim Diaper
Will they soak up urine? Do not soak up urine Do not soak up urine
Are they reusable? Can be reused multiple times so are more eco-friendly than disposables. No. They will last for the duration of a swimming session but can only be used once
How do they stop leaks? Feature tightly woven fabric and secure but comfortable leg and tummy cuffs to fully contain any faeces. Although disposable swim diapers have leak guards around the legs, these are very limited in preventing faeces from entering the pool. 
What swimwear can they be worn with? Can be used on their own, underneath regular swimwear or over the top of a disposable swim diaper or liner. Can be used on their own, underneath regular swimwear or underneath a reusable swim diapers.
How expensive are they?

More expensive than disposable diapers but can be more cost-effective if used regularly. Approx. $17 per pair.

Cheap to buy. Approx. $10 for a pack of 12.

What brands should I look for?

Splash About Happy Nappy™ is the leading reusable swim diaper. 

Huggies Little Swimmers and Pampers Splashers are amongst the best known brands.


Swim Diaper Size Guide

Disposable swim diapers come in set sizes similar to standard diaper sizes – most brands sell nappies in the following sizes:

  • 2-3 (to fit babies who weigh approx. 6 - 17lbs)
  • 3-4 (to fit babies who weigh approx. 15 - 33lbs)
  • 5-6 (to fit babies who weigh approx. 26 - 39lbs)

These numbers refer to the diaper size and not the age of the child, so choose a size similar to your child’s regular diapers. Choose a snug but comfortable fit to minimise the risk of leaks.

Some disposable swim diapers designed for smaller children have adjustable tabs for a more secure fit. 

Reusable swim diapers are sized by children’s ages – 0-3 months, 3-6 months, 6-12 months and so on. Your child’s age should be used as a guide for buying a reusable swim diaper but it’s important to also measure your child’s waist and thighs for the best fit.

Swim diapers look like regular swimming shorts and should fit snuggly at the waist and thighs and be tight enough without leaving a red mark. Click on any Happy Nappy™ on the Splash About website and follow the ‘Check Size Before You Buy’ link for a size calculator to ensure the best fit.


Age Range

Waist Circumference Thigh Circumference
X Small -Newborn 12.2 - 14.2 in 5.9 - 7.9 in
Small - 0-3 Months 13.4 - 16.1 in 6.9 - 7.9 in
Medium - 3-6 Months 14.6 - 17.3 in 7.5 – 9.5 in
Large - 6-12 Months 15.7 – 18.5 in 7.8 – 10.2 in
X Large - 1-2 Years 16.5 – 19.7 in 8.7 – 12.2 in
XX Large - 2-3 Years 17.3 – 20.5 in 10.2 – 13 in
3-4 Years 18 – 21 in 10.5 – 14 in
4-5 Years 22 – 24 in 11.5 – 15 in

Waist : Measure the circumference of the fullest part of the waist

Thigh: Measure the circumference of the fullest part of the thigh



5 Top tips for using swim diapers

  1. Disposable swim diapers are not very effective at preventing feces from entering the pool, especially looser stools. If your child has had diarrhea then skip the swimming session until they are completely better.
  2. No swim diaper can contain urine, so don’t put them on your child too soon! Urine in the pool is not a problem as the chemicals in the pool are strong enough to kill any germs.Diarrhea
  3. Regular diapers should not be used for swimming as they absorb too much water, making them extremely heavy, which can be dangerous for little ones.
  4. Check your baby’s swim diaper regularly and change immediately if soiled.
  5. Ensure toddlers have a potty break every 30 - 60 minutes. Most leaks into pools come from toddlers who can’t hold it or are so excited they forget to hold it.


The Happy Nappy™ Swim Diaper

Splash About is the leading brand in reusable swim nappies. The Happy Nappy™ swim diaper is made from neoprene. Its patented, unique shape is designed to fit baby's butt and move as they do, preventing any gaping and stopping fecal leaks into the pool. The award-winning Happy Nappy™ swim diaper is recommended by swim schools for swimming lessons worldwide, and for good reason! We have not had a reported leak in the Happy Nappy™ for over 8 Years! Available in a wide range of colours and designs, the Happy Nappy™ swim diaper really is a swimming lesson essential. 

Step-by-step guide to using a reusable swim diaper

Reusable swim diapers are simple to use. Just follow these steps:

  • Put the reusable diaper on your child. Most reusable swim diapers work efficiently without any other diaper underneath, however some swim schools insist on a double diaper system. In this case reusable diapers can be worn with a disposable underneath or a reusable Diaper Wrap and Liners. If you choose the Happy Nappy Duo™ , with a second layer incorporated, there is no need for any other under diaper at all.
  • Put your child’s regular swimwear over the reusable swim diaper or just use the diaper on its own. The Splash About Happy Nappy™ is designed to look like regular swimwear so can be worn on its own.
  • Regularly check your child’s swim diaper for soiling.
  • If your child has a bowel movement, change them immediately in the baby change facilities, not at the side of the pool.
  • Remove the soiled liner from the Diaper Wrap, if using, and flush this away. If you don’t use a liner or Diaper Wrap, simply tip the feces off the swim diaper into the toilet and flush it away.
  • Rinse the swim diaper in cold water and store in a plastic bag.
  • If you want to continue swimming then simply rinse the swim diaper and your child can put it back on.
  • To clean a soiled reusable swim diaper hand wash in cool water and leave to dry away from direct sunlight.


How many swim diapers do I need?

Disposable swim diapers are designed to be used just once. If your child will be spending long periods out of the water (e.g. exploring the beach or having lunch at the swimming pool) then pack enough to ensure they have a clean, dry swim diaper every time they get back in the water. Wearing wet disposable swim diapers for extended periods out of the water can be uncomfortable for children and lead to diaper rash or chafing.If your child is suffering from diaper rash and you're worried about taking them swimming, find out how the Splash About Happy Nappy™ can help protect your little one's delicate skin.

Reusable swim diapers work just like regular swimwear so shouldn’t cause soreness or chafing. As they do not hold in urine, they should be swapped for a regular diaper as soon as the baby gets out of the water. They are quick drying, so can be left to dry whilst out of the pool and reused when the baby returns to the water. At most, you should only require 2 reusable swim diapers to use on rotation so you always have a clean, dry swim nappy to hand in case of accidents.

Remember – disposable and reusable swim diapers are NOT designed to hold in urine so make sure you take your child for regular potty breaks or switch to a normal disposable diaper when they’re not in the pool.


Swim diaper FAQs

When should I stop using swim diaper?
Once your child is potty trained and you are confident they will tell you when they need a poop you can stop using swim diapers. Splash About’s Happy Nappy™ range is suitable for children up to 3 years old and look just like regular swimwear, so if your child has recently been potty trained, this range can give you peace of mind that there will be no leaks should an accident happen.

How do I clean and care for reusable swim diaper?
Reusable diapers can be hand washed in cool water.

What are reusable swim diaper made from?
The Splash About Happy Nappy™ swim diaper range is made from super soft 1mm thick neoprene. This fabric is water resistant and helps to keep a snug fit over your baby’s butt. The neoprene used is a much thinner and softer neoprene to that used to make wetsuits.

How long will a swim diaper contain feces for?
Swim diapers are designed to hold feces long enough for you and your little one to leave the pool without any leakage. They are not designed to hold feces for a long period so you should ensure that you leave the pool immediately.

Will a swim diaper contain a loose stool?
Disposable swim diapers may not contain loose stools as they are not very robust and can leak around the seams. The Happy Nappy™ swim diaper features wide cuffs made from specialist fabric which creates a tight (but comfortable) seal around the thighs and tummy, which will keep solid and semi-solid feces at bay.

While very loose stools are completely normal for young babies that are exclusively breastfed, if your child is older and is experiencing diarrhea, then it’s important to keep them away from the water until they feel better.

Can my child wear a regular disposable diaper under a reusable swim diaper?
No, regular disposable diapers are designed to soak up liquid so can become bulky and uncomfortable very quickly if submerged in a swimming pool. However, disposable swim diapers can be worn under a reusable swim diaper.

What should my child wear under a reusable swim diaper?

Most reusable swim diapers can be worn on their own, however, for extra protection you may want to combine with a disposable swim diaper, a Diaper Wrap, and/or liner.

Some swimming pools and swim schools insist on a disposable swim diaper being worn under a reusable one, whilst others insist on the Happy Nappy Duo™ or double layer diaper system, so check your local pool’s policy

Are swim diapers suitable for boys and girls?
Absolutely. The Splash About Happy Nappy™ comes in a range of designs suitable for boys and girls, or unisex designs suitable for both.

You can view Splash About’s full range of Happy Nappy™ swimwear here.

Unsure about what to dress your baby in at the pool or beach? Read our guide Where to Start: Baby Swimwear Essentials

What about sizes for older children?
Most disposable and reusable swim diapers are suitable for children up to the age of three. There are a number of reasons why children older than this may require swim diapers:

  • Potty training is taking a little longer
  • Your local pool requires all children under a certain age to use swim diapers
  • Your child is affected by faecal incontinence

Splash About Toddler Jammers are available in 2-3 Years or 3-4 Years and also available are our Kids Jammers which are designed to fit children up to the age of 9 and should a fecal accident happen, it won’t leak into the pool. They look just like swimming shorts and can be worn on their own or worn with other swimwear.

Toddler Jammers

Available in 2-3 Years and 3-4 Years, these Toddler Jammers are designed to provide the same leak protection as the Happy Nappy™ swim diaper in a grown-up shorts design. The Toddler Splash Jammers are recommened by swim schools worldwide. 

Happy Nappy™ and Happy Nappy Duo™ Swim Diaper 3T and 4T

Our well loved Happy Nappy™ and Happy Nappy Duo™ is now available in selected styles in sizes 3-4 years and 4-5 years. This gives another option to parents of toddlers who still need swim diaper support and who know and trust the Happy Nappy™ and its benefits.

Kids & Adult Jammers

Available in kids sizes up to 9 Years and Adults from X-Small to X-Large, they work in the same way as the Toddler Jammers, with a snug fitting waist rib and silicone seal on the thighs to keep in all solid leaks. They look just like swimming shorts and can be worn on their own or worn with other swimwear over the top.