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Published 22/11/2023

Fit Guide - How our Baby Swimwear should fit.

Many Splash About baby swimming products depend on a good fit, so getting the right size is imperative. Others do not need to fit as accurately. In this guide, we will look at each product type and advise the best way to measure and explain how it should fit.

Happy Nappy™ & Happy Nappy Duo™ Swim Diapers

The Happy Nappy™ and Happy Nappy Duo™ swim diapers rely on proper fitting. They have specialized ribs around the thighs and waist to contain solids within the nappy, which must fit snugly against the child’s skin. For optimal leak protection and comfort, the Happy Nappy™ swim diaper should fit closely to maintain a secure seal. However, you should also ensure that there is enough space to run a finger around the inside of the seal to prevent chafing or redness.

When the Happy Nappy™ swim diaper fits correctly, it should cup the baby’s butt, with the back of the diaper sitting slightly higher than the front. The top of the diaper should come up to the belly button and the thigh seals should sit at the top of the baby’s thighs. The ribs should not cut into the skin.

How to measure for a Happy Nappy™ or a Happy Nappy Duo™ Swim Diaper

To ensure the best fit for your baby, it is strongly recommended to use our size guide. Whilst the Happy Nappy™ and Happy Nappy Duo™ Swim diapers have age range sizes, these are a guide only. Babies come in all shapes and sizes and one diaper size will not fit every baby in that range.

Do not measure your baby straight after feeding as this could affect the measurements.

Lie baby down and measure the circumference of their body, placing the tape measure over the belly button. Then measure the circumference of the fullest part of their thigh.

Use these measurements to refer to our size guide to get the correct fitting Happy Nappy™ or Happy Nappy Duo™ swim diaper. Remember, the age is just a guide, don’t be put off if it does not come out as you’d expect.

Happy Nappy™ and Happy Nappy Duo™ Size Guide

  Waist Thigh
0-3 Months (Small) 13.4 - 16.1 in 6.7 - 8.7 in
3-6 Months (Medium) 14.6 - 17.3 in 7.5 - 9.5 in
6-12 Months (Large) 15.7 – 18.5 in 7.9 – 10.2 in
12-24 Months (X Large) 16.5 – 19.7 in 8.7-12.2 in
2-3 Years (XX Large) 17.3 – 20.5 in 10.2 - 13 in
3-4 Years (3T) 18 – 21 in 10.6 - 13.8 in
4-5 Years (4T) 22 – 24 in 11.4- 14.6 in

Happy Nappy™ Wetsuit & Happy Nappy™ Sunsuit

Our Happy Nappy™ Wetsuit and Sunsuits rely on the same proper fitting as the Happy Nappy™ and Happy Nappy Duo™ swim diapers, as they both include an integrated Happy Nappy™. As such, please use the rules above for measuring the fit of the Happy Nappy swim diaper. It is also useful to measure the baby’s chest and height to make sure the suit fits correctly all over. The Happy Nappy™ Wetsuit works like an adult wetsuit and therefore, does need to fit closely to trap a layer of water that keeps baby warm when in water. The Sunsuit can be worn with some room at the top, as long as the Happy Nappy™ bottom fits as above.

How to measure for a Happy Nappy™ Wetsuit or Sunsuit

It is important to use the correct size guide for these products as they are sized slightly differently to the Happy Nappy™ and Happy Nappy Duo™ swim diapers. Again, the age range sizes are only a guide and the size guide must be used to ensure you get the right fit.

As with the Happy Nappy™ and Happy Nappy Duo™, do not measure baby when they have just had a feed. Measure the circumference of the tummy, across the belly button, and then the thigh, across the fullest part. Once those measurements have been obtained, you can measure the baby’s chest and height. The chest circumference should be taken with the tape under the baby’s arms, across the fullest part of the chest. Height should be measured from the top of the shoulder to the crotch.

Use these measurements to refer to the size guide to find the correct fit, remembering the Happy Nappy™ part should be close fitting but not too tight. If your measurements do not fit within our guide ranges, please eamil our customer services team on [email protected] who will be happy to advise you.

Happy Nappy™ Wetsuit & Happy Nappy™ Sunsuit Size Guide

  Waist Thigh Chest Shoulder to Crotch
3-8 Months (Medium) 15.7 – 18.1 in 7.9 – 10.2 in 18.1 – 19.7 in 15.7 – 16.9 in
6-12 Months (Large) 16.9 – 18.5 in 8.7 – 11 in 18.9 – 21.2 in 17.3 - 20 in
12-24 Months (X Large) 17.7 – 20 in 9.4 – 11.8 in 20.5 – 22 in 18.9 – 20 in

Happy Nappy™ Swimsuit

The Happy Nappy™ Swimsuit follows the same measuring rules as the Happy Nappy™ Wetsuit and Happy Nappy™ Sunsuit. Again, the Happy Nappy™ swom diaper part of the costume needs to fit as per the Happy Nappy™ guides at the top of the article, but the top does not have to fit tightly. It is made with thick straps that won’t fall down, even if it is a bit bigger on the top.

How to measure for a Happy Nappy™ Swimsuit

As with the Happy Nappy™ and Happy Nappy Duo™ swim diapers, avoid measuring the baby after a feed. Start by measuring the tummy circumference, taken across the belly button, and then measure the thigh circumference at its fullest part. Then, measure the baby’s chest and height. To measure the chest circumference, place the tape under the baby’s arms, around the fullest part of the chest. Height should be measured from the top of the shoulder to the crotch.

Use these measurements to refer to the size guide to find the correct fit. Remember, the Happy Nappy™ bottom should be snug but not excessively tight. If your measurements fall outside of our guide ranges, please contact our customer services team on [email protected]

Happy Nappy™ Costume Size Guide

  Waist Thigh Chest Shoulder to Crotch
3-8 Months (Medium) 15.7 – 18.1 in 7.9 – 10.2 in 18.1 – 19.7 in 15.7 – 16.9 in
6-12 Months (Large) 16.9 – 18.5 in 8.7 – 11 in 18.9 – 21.2 in 17.3 - 20 in
12-24 Months (X Large) 17.7 – 20 in 9.4 – 11.8 in 20.5 – 22 in 18.9 – 20 in
2-3 Years (XX Large) 20 – 20.5 in 10.2 – 12.6 in 21.3 – 23.6 in  20.5 – 21.7 in

Baby Wrap Wetsuit

The Baby Wrap is a baby wetsuit that doesn’t have to fit precisely. In fact it has been designed to allow for growing room so it could potentially fit a baby for several months. It has hook and loop fastenings over the shoulders and down the front which can be adjusted every wear to accommodate a growing baby.

The Baby Wrap covers the core of the body in 2mm thick neoprene, which keeps babies warm, even if it is not snug to their body.

How to measure for a Baby Wrap

To find the correct Baby Wrap size, you will need to measure your baby’s chest circumference and height from shoulder to crotch.

To measure the chest, wrap the tape measure around the fullest part of your baby’s chest, under their arms and around their back. You will then need the measurement from the top of their shoulder to their crotch as shown in the image below:

Remember Baby Wraps are designed to last for several months so if your baby is at the top end of a size, it may be worth considering the next size up to ensure you get plenty of wear.

Once your measurements have been obtained, refer to our size guide to find the perfect fit.

Baby Wrap Size Guide

  Chest Shoulder to Crotch
6-18 Months (Medium) 19.3 - 20.9 in 16.5 - 17.7 in
18-30 Months (Large) 21.3 – 22.8 in 16.9 – 18.11 in

Warm in One Wetsuit

The Warm in One is a fleece lined full body suit. Unlike the Happy Nappy™ Wetsuit, it does not have to fit closely, it can be worn slightly oversized. It is designed to have long sleeves and legs, but can be worn slightly shorter to allow for growth.

How to measure for a Warm In One

To find the correct fit, measure the circumference of your baby’s chest—under their arms and around their back—and the length from the highest point of their shoulder to their crotch

Once you have your measurements, refer to our size guide to help you choose the correct size. If your baby’s measurements fall in the top range of a size, consider buying the next size up.

Warm In One Size Guide

  Chest Shoulder to Crotch
3-6 Months (Medium) 20.5 - 22 in 13 - 14.2 in
6-12 Months (Large) 22 – 23.6 in  14.6 – 15.4 in
12-24 Months (X Large) 23.6 – 25.2 in 15.7 – 16.9 in