Everything You Need to Know About TSA Liquid Rules

Dealing with airport security can be one of the more daunting aspects of air travel, from the detailed rules about what you can and can't bring on board to the long lines that often form at checkpoints.

One rule that frequently trips up travelers is the Transportation Security Administration's (TSA) 3-1-1 regarding liquids in carry-on bags. We're here to walk you through the finer details of the rule and provide helpful tips for packing liquids when you're flying.

What is the TSA's 3-1-1 rule?

In 2006, British security officials thwarted a plot to bomb an aircraft with liquid explosives carried on board. Since then, security agencies around the world have limited the amount of liquid passengers can bring through airport security.

For the TSA, which regulates travel in the United States, all liquids, gels, and aerosols must be in containers that are 3.4 ounces (100 milliliters) or less. All liquids must fit into a single, clear quart-size bag — passengers can only pack one of these bags in their carry-on.

The 3-1-1 designation is a simple way to remember these numbers: individual liquid containers must be 3.4 ounces or smaller, they must fit into one clear, quart-size bag, and there is only one bag allowed per passenger.

Liquids that do not comply with the 3-1-1 rule must be packed in checked bags, or thrown out at airport security. Some liquids, such as gasoline or other flammable liquids, are prohibited entirely, both in checked and carry-on bags. You can find a full list of permitted and prohibited items on the TSA's website.

If you're unsure if a specific item adheres to the 3-1-1 rule, you can always contact the TSA before your trip. "Tweet your questions and comments to @AskTSA or via Facebook Messenger, weekdays from 8 a.m. to 6 p.m. ET," TSA spokesperson Jessica Mayle tells Travel + Leisure. "You can also call the TSA Contact Center at 866-289-9673."

Are there any exceptions to the 3-1-1 rule?

The TSA does exempt some items from the 3-1-1 rule: medically necessary liquids, formula, and breast milk. You can bring more than 3.4 ounces of these liquids on board, but you may have to undergo additional security screening.

"Inform the TSA officer at the beginning of the screening process that you're carrying them," says Mayle. "These liquids are typically screened by X-ray, but TSA officers may also test them separately for explosives or concealed prohibited items. Officers may ask you to open the container and/or have you transfer a small quantity of the liquid to a separate empty container, or dispose of a small quantity, if feasible."

If you don't want your exempt liquids to be screened by X-ray, inform your TSA officer, and they will use alternative security measures to clear the items.

And that's not all. "There's an exception for hand sanitizer, which has a temporary 12-ounce limit," says Mayle. But as COVID-19 travel restrictions and protocols continue to lift, the temporary special case for hand sanitizer could change, too.

Another exception is liquids purchased after security in an airport. In domestic U.S. airports, you can bring nonalcoholic drinks and other liquid items purchased airside onto your flight. (This is not always the case in international airports.) Duty-free liquids, however, will be sealed in a tamper-safe bag before boarding — sometimes they're permitted in the cabin, and other times they may be stowed elsewhere on the plane.

Packing Tips for Liquids in Carry-on Bags

• While many products are sold in 3.4-ounce containers suitable for travel, not all of them are. Consider rebottling your liquids into travel-size, leak-proof cases.
• "Another way to save space in your quart-sized bag is to pack solid versions of products, which you can put in your luggage or carry-on bag without needing to place it in the quart-size bag," travel advisor Ateet Ahuja of Complete Getaways tells T+ L. "For example, you can bring a stick or solid version of some perfumes and shampoo bars instead of liquid shampoo."
• Buy your liquids, like shampoo or mouthwash, at your final destination. "While you'll spend a little extra, the cost far outweighs the potential of it spilling or leaking in your bag," says Ahuja.
• On that note, prepare for spills — Ahuja advises wrapping a small hand towel around your quart-size bag.
• Pack your nonliquid toiletries separately to save space in your quart-sized bag.
• Pack your liquids bag in an easy-to-access space, like an external compartment or the top of your carry-on bag. According to Ahuja, "This will save you time in the TSA line."