Can You Take Slime on a Plane? Carry-On and Checked Bag Rules (2026)

Many parents whose children love slime ask whether you can take slime on a plane. The short answer is yes. But airport security treats slime as a liquid. In your hand luggage, it has to be in a container of 100 ml (3.4 oz) or less and go in your liquids bag with your toiletries. In checked luggage, you can pack as much slime as you like.

Quick answer

How to get slime through airport security

According to the US Transportation Security Administration (TSA), passengers may carry liquids, gels and aerosols in containers of 3.4 ounces (100 ml) or less. All of them must fit in one quart-size (about 1 litre) clear plastic bag, and each passenger gets one bag. EU and UK airports use the same principle with a 100 ml limit.

To take slime in your carry-on:

1. Put the slime in a small container of 100 ml (3.4 oz) or less. Small screw-top travel jars work well.
2. Make sure the size is visible. Security staff go by the container’s size, not by how full it is. A large tub with a little slime in it can still be taken away. Many store-bought slimes don’t show the volume on the lid, so a labelled travel jar is safer.
3. Put the container in your liquids bag with your toothpaste and shampoo.
4. Take the liquids bag out at security if the airport asks you to.

It doesn’t matter whether the slime is homemade or bought from a shop. TSA’s What Can I Bring? list doesn’t mention slime by name, but when I asked AskTSA, the answer was: yes, as long as it is 3.4 ounces or less and in the liquids bag. The final decision is always up to the security officer at the checkpoint.

European airports and the 100 ml rule

Some European airports have installed new CT scanners that can screen liquids inside bags, and a few of them allow containers of up to 2 litres. However, in 2024 the EU reinstated the 100 ml limit for many of these scanners, and the rules now vary from airport to airport. The safest assumption is that the 100 ml rule applies, unless your departure airport’s website clearly says otherwise. Remember that the rules on your return flight may be different.

Why does slime count as a liquid?

Slime doesn’t feel like a liquid such as water, but it isn’t a solid like wood either. There are four states of matter: solid, liquid, gas and plasma.

• A liquid takes the shape of its container but keeps nearly the same volume.
• A solid keeps its own shape and resists force applied to it.
• A gas expands to fill all the space available.
• Plasma is an ionised gas that conducts electricity.

Slime fits best with liquids, because it slowly takes the shape of its container. More precisely, slime is a non-Newtonian fluid: its viscosity changes when you apply force. Pull it slowly and it stretches; pull it quickly and it snaps. For airport security, slime is treated like other thick liquids and gels, such as toothpaste, shampoo and honey.

Tips for flying with slime

• Take only a little in the carry-on. One or two small jars keep a child busy, and the rest can go in the checked bag.
• Seal it well. Air pressure changes during the flight, so close the lid tightly and put the container in a zip bag.
• Leave out activator liquids and powders. Slime activators and borax are not needed on the plane. If you take powders in a US carry-on, larger amounts may need extra screening.
• Keep it away from fabric. Slime is hard to get out of airline seats and clothes. Give it to your child on the tray table, with a wet wipe at hand.
• Have a back-up plan. If security takes the slime, a small toy, a sticker book or a colouring book can save the flight.

Slime-free alternatives for the flight

If you don’t want to deal with the liquids rule at all, these are not liquids and can go in the carry-on freely:

• a fidget toy or squishy toy
• sticker books and reusable sticker pads
• small LEGO sets in a zip bag.