Snap-Crotch Onesies

(a.k.a Bodysuits)

So many snaps!

First, A History Lesson

Everyone has a different name for this garment. Let’s clear up the confusion.

The Gerber Corporation trademarked the names Onesies® which means that many creative names have been invented to describe them such as snapsuits and bodysuits. Sometimes one-piece pajamas are also called onesies but those are a totally different (but cozy!) kind of clothing.

What To Look For

Onesies fit everyone differently and there are a few qualities to look for when checking whether a onesie is right for you.

Crotch Width

An extra-wide crotch and a full cut bottom for bulky diapers

The width and shape of the crotch differ greatly between brands. A wider crotch allows the fabric to ride up between the legs creating a barrier between the diaper and the thighs. This can reduce chafing but it can also be a problem. Depending on the material, the construction of the seams, and whether the snaps also touch the thighs, it could rub uncomfortably with prolonged walking

Knowing what to look for can help you know whether a new bodysuit is going to work for you while you still have a chance to return it.


Be wary of onesies with only two snaps. This means the crotch is narrow. Sometimes this is intentional and allows the onesie to be worn without riding up between the legs. However, some adult onesies with two snaps aren’t made to be worn over diapers. You can tell because the crotch is cut like women’s panties.

This bodysuit has a full cut made for diapers. The crotch is narrow with two metal snaps which lets it securely hold up the middle of a diaper without rubbing the thighs.

Snaps can be made of metal or plastic. Metal snaps are more durable but they can also be difficult to remove. If the snaps are hard to undo, be extra gentle when removing them because the fabric can stretch or rip around them.


Measuring the right onesie length is very different from measuring t-shirts or pants. Finding the right length is usually more important than the width.

You want it to be tight enough to support a weighty diaper but not so tight that it causes leaks or discomfort. If you wear a wide variety of diaper thicknesses, you may find having different sizes helps you find the best fit for any occasion.

Some manufactures offer multiple bodysuit lengths for people of different heights and proportions.

Extra Features

A lap-neck onesie from LittleForBig
  • shoulder snaps Allows the onesies to be pulled down or removed without unsnapping the crotch. Sometimes this is easier to access than the harder-to-reach crotch snaps.
  • lap neck A very babyish extra-wide neck opening that overlaps near the shoulders. It opens up easily to pull the onesie off without messing with any snaps.
  • built-in mitts Some bodysuit-makers have long-sleeve versions with padded mitts on the end to keep wandering hands under control.