Airport security can be one of the most unpredictable and frustrating parts of air travel. Between long lines and the lengthy list of regulations from the Transportation Security Administration, travelers can sometimes find themselves scrambling at checkpoints.
But perhaps no rule is more misunderstood than the TSA’s Liquids, Aerosols, and Gels Rule, specifically, the 3-1-1 policy for carry-on bags. From what you need to know about TSA’s liquid requirements to helpful packing strategies, here’s everything you need to know before your next security screening.
What is TSA’s 3-1-1 rule?
TSA’s 3-1-1 policy was introduced in 2006 after British officials stopped a plot to detonate liquid explosives on board international flights headed to the U.S. After that, airports around the world started adopting stricter screening standards.
In the U.S., TSA requires all liquids, gels, and aerosols in carry-on bags to be in containers of 3.4 fluid ounces (100 milliliters) or smaller. These containers must fit into a single, clear quart-size bag, and only one bag is allowed per passenger. The “3-1-1” designation refers to these three conditions: 3.4 ounces in one bag for one person.
“Clients often forget about water bottles, full-size sunscreens, or skincare items in their carry-ons,” says Travel + Leisure A-List Travel Advisor Laura Asilis. “Perfumes and face mists are common culprits too, especially when travelers are rushing and forget they’re in handbags or amenity kits.”
Kristin Diehl, another A-List Travel Advisor, says the thick consistency of sunscreen makes it easy for travelers to overlook. She also notes her clients tend to have products thrown out when they’re in larger containers, even if there are less than 3.4 ounces of liquid left.
According to TSA press secretary R. Carter Langston, the most common liquid mistake is forgotten water bottles. If you are carrying more than 3.4 ounces of liquid in a single container (even if it’s water), you will have to discard it before entering security. Volatile liquids, such as gasoline and other flammable substances, aren’t allowed in either carry-on or checked bags, and it’s a good idea to not bring them to the airport at all.
Kaitlyn Collins/Travel + Leisure
Are there any exceptions to the 3-1-1 rule?
There are multiple exceptions to the 3-1-1 rule.
“Medically necessary liquids, including breast milk and baby formula, should be declared to an officer in the checkpoint,” says Langston. “They still need to be screened, but they are permitted.”
Exempt liquids include prescription eye drops, liquid medications, and hydration or nutritional supplements for chronic conditions or disabilities. While TSA doesn’t require a doctor’s note, Asilis says documentation can help make the screening process quicker, especially when traveling with less common items.
Travelers with disabilities and medical conditions have additional allowances. TSA allows for liquids needed for medical devices to bypass the 3.4-ounce limit. These include cleaning solutions for mobility aids or distilled water for CPAP machines. Like other medical exemptions, these items should be declared to security officers at the checkpoint.
If you’re traveling with duty-free liquids purchased internationally, Langston says, “the duty-free store will package the liquids for travel in a transparent, secure, tamper-evident bag.” He also notes that the bag cannot show any signs of tampering and must have been purchased within the past 48 hours. You should also keep the receipt on you.
While less commonly known, you can also bring liquids through security if they’re completely frozen solid—but keep in mind that the enforcement of this rule will be up to the officer that you encounter at the checkpoint. “It can technically work, but it’s risky,” says Asilis. “TSA allows frozen items if they’re solid at screening—but if partially melted, they may be confiscated. I advise against relying on this trick unless truly necessary.”
Will TSA liquid rules change soon?
There have been whispers in the travel world that these restrictions may be easing in the near future. Asilis says that some international airport terminals—such as Amsterdam Airport Schiphol (AMS)—have lightened liquid restrictions by introducing new computed tomography scanner technology. With CT scans, officers can detect liquids that might be dangerous without having travelers remove liquids from their bags.
“Airports with newer CT scanners are more flexible,” Asilis says. “But since implementation isn’t widespread, I still advise clients to follow the standard 3-1-1 rule.”
But will the rules actually change anytime soon for those in the United States? According to Langston, CT technology is projected to be at full operating capacity around 2042, but TSA will continue to evaluate its screening strategies until then.
Packing Tips for Liquids in Carry-on Bags
To make your airport experience as quick and disturbance-free as possible, consider these expert packing strategies:
“Use clear, zippered pouches and prepack your TSA liquids bag at home,” says Asilis. “Put all non-essential liquid toiletries (like full-size shampoo, face wash, etc.) in your checked luggage, and only keep the essential liquid items (like hand sanitizer, eye drops, lip balm, etc. ) in your carry-on inside the TSA-approved quart-size bag.”
As for personal hygiene and beauty products, Diehl recommends asking for sample packets at the salon. “They’re TSA-compliant, take up minimal space, and streamline carry-on organization,” says Diehl. “Plus, you won’t have to worry about repacking them for your return trip.”
Asilis also recommends grouping items by category and using small travel containers with clear labels. “I suggest placing the bag in an outer pocket of the carry-on for easy access during screening,” she says.
Additionally, using solid alternatives to liquid items can help maximize space in your quart-sized bag. “I often recommend shampoo and conditioner bars, sunscreen sticks, solid perfumes, and even toothpaste tablets,” says Asilis. “These are especially helpful for frequent travelers and avoid waste or mess.”
Still unsure about whether something complies with TSA regulations or not? The agency has plenty of resources to help. The Liquids, Aerosols, and Gels Rule page on the TSA website has additional information, and travelers can also contact AskTSA via X Post, Facebook Messenger, Apple Messages, or by texting “Travel” to AskTSA (275-872). Langston says the live assistance is available from 8 a.m. to 6 p.m. Eastern time.
