Liquids must be in a clear bag at airport security, but only if you're carrying them through the checkpoint

The 3-1-1 rule requires liquids, gels, and aerosols in your carry-on to be in a single clear plastic bag when you go through the security line. Each container must be 3.4 ounces (100 milliliters) or smaller, and they all fit in one quart-sized clear bag. You remove this bag at the checkpoint and place it in the bin with your shoes and electronics.

The bag itself doesn't have to be brand new or pristine—it just needs to be clear enough for the officer to see inside without opening it. A gallon-sized freezer bag works fine. Once you're past security and in the gate area, you can take items out and use them normally.

Liquids in checked baggage don't need to be in a clear bag at all. They can stay in your regular suitcase, though some items (like certain flammables) are prohibited in checked bags entirely. The clear bag rule applies only to what you carry onto the plane.

Key Takeaways

  • All liquids, gels, and aerosols in carry-on bags must go in one clear quart-sized bag at the security checkpoint.
  • Each individual container can hold no more than 3.4 ounces (100 milliliters).
  • You remove the bag at security and place it in the screening bin; you can use the items after you pass through.
  • Liquids in checked baggage do not need to be in a clear bag, though some liquids are banned from checked bags entirely.
  • The clear bag rule is a security screening requirement, not a packing rule for the plane itself.

What counts as a liquid under the 3-1-1 rule

Liquids include obvious things like water, juice, and shampoo, but also items that look solid. Peanut butter, yogurt, honey, hummus, and jams all count as liquids because they're spreadable or pourable. Toothpaste, deodorant, and hair gel are gels. Spray sunscreen, hairspray, and bug spray are aerosols. All of these go in the clear bag.

Solid foods like fruit, sandwiches, and cheese do not need to be in the bag. Powders like talc, baby powder, and protein powder are restricted to 12 ounces (350 milliliters) in carry-on bags and are screened separately—don't put them in the liquid bag. Medications in liquid form (like cough syrup) are allowed in reasonable quantities beyond the 3.4-ounce limit if you declare them, but it's simpler to pack them in checked baggage when possible.

How to pack your clear bag correctly

Buy a quart-sized clear plastic bag (the kind used for freezing food) or use one you already have at home. Place all your 3.4-ounce containers inside, seal it, and keep it easily accessible in your carry-on—not at the bottom under everything else. At the checkpoint, remove it before you reach the officer and place it in the screening bin on top of your other items.

Don't overstuff the bag. If containers are crushed or the bag is bulging, the officer may ask you to repack it or may confiscate items. Leave a little room so everything sits flat. If you're traveling with a partner or family, each person needs their own clear bag; you can't combine everyone's liquids into one.

What happens if you forget the clear bag

If you reach security without a clear bag, the officer will likely ask you to step aside. You have a few options: buy a clear bag at a shop in the terminal if one is nearby, repack your items into a bag you find, or surrender the liquids. Some airports have clear bags available at the checkpoint, but don't count on it.

If you're running late, surrendering the liquids is faster than repacking. You can buy travel-sized versions of shampoo, lotion, and other toiletries after you pass security, or wait until you reach your destination. It's not ideal, but it won't delay your flight.

Exceptions and special cases

Medications in liquid form (insulin, cough syrup, liquid vitamins) are allowed in quantities larger than 3.4 ounces if you declare them to the officer. Keep them separate from your clear bag and tell the officer about them before screening begins. Baby formula and breast milk are also exempt from the 3-1-1 rule in reasonable quantities; again, declare them upfront.

Duty-free liquids purchased after you pass security can be carried onto the plane in the sealed bag they came in, even if they're larger than 3.4 ounces. However, if you have a connecting flight, you'll need to pack them in checked baggage for the second leg or they'll be confiscated at the next checkpoint.

International travel and different rules

The 3-1-1 rule applies to flights departing from the United States. If you're flying internationally from a U.S. airport, the rule still applies. However, other countries have different rules for their own airports. If you're flying from Europe, Asia, or another region, check that country's aviation authority website for their liquid restrictions before you pack.

When you return to the U.S., the 3-1-1 rule applies again at your departure airport abroad. Some international airports are stricter than U.S. airports, so arriving early is wise if you're unsure about the rules.

Frequently Asked Questions

Can I use a bag that's not completely clear?

The bag needs to be clear enough for a security officer to see the contents without opening it. A frosted or slightly cloudy bag usually works, but a completely opaque bag will not. When in doubt, use a standard freezer bag—they're inexpensive and widely available.

What if my liquid container is 3.5 ounces instead of 3.4?

Containers larger than 3.4 ounces (100 milliliters) are not allowed in carry-on bags, even if they're only slightly over. The officer will confiscate it. Buy a smaller size or pack it in checked baggage instead.

Do I need a clear bag for a domestic flight?

Yes. The 3-1-1 rule applies to all flights departing from U.S. airports, whether domestic or international. There is no exception for short flights or familiar routes.

Can I pack my clear bag in my checked bag instead?

You can, but there's no reason to. The clear bag is only required at the security checkpoint for carry-on screening. Once you're past security, you can remove items from the bag and use them. If you're checking a bag, liquids can go directly into it without the clear bag.

What if the officer says my bag is too large?

A quart-sized bag is the standard, but if an officer says yours is too large, repack into a smaller bag or remove some items. Don't argue—just comply. If you're regularly traveling with many liquids, consider checking a bag instead so you can bring full-sized bottles.