The carry-on liquid rule is the most misunderstood rule in air travel. For twenty years it has been the same everywhere: containers of 100 milliliters or less, all in a single transparent resealable bag of about one liter. In 2026 that rule is changing, but not everywhere and not at the same speed, which is exactly why travelers keep getting their toiletries confiscated at some airports and waved through at others.

The change comes from new CT scanners. Airports that have installed them can see inside bags in three dimensions, and their security teams no longer need the 100ml limit or the plastic bag. In the UK, several major airports have lifted the limit to two liters per container for passengers passing through the new scanners, while airports still using older machines keep the old rule. In the EU, the rollout has been uneven and some airports that lifted the limit have reinstated it temporarily while the new scanners are certified. The result is a patchwork: the rule depends on the airport, the terminal, and sometimes the lane you happen to join.

The safe approach is to pack for the strictest rule on your journey. If any airport on your trip still enforces 100ml, pack to that limit and you will pass everywhere. Put every liquid, gel, cream, and paste in containers of 100ml or less, inside a single clear resealable bag, and keep the bag at the top of your carry-on so you can pull it out fast. Liquids include the things people forget: toothpaste, sunscreen, contact lens solution, liquid makeup, and hand sanitizer. A full-size deodorant, a 200ml moisturizer, or a large sunscreen will be confiscated at a strict airport, no matter how expensive it was.

There are exceptions worth knowing. Medication is exempt from the limit, but carry the prescription or a doctor's note and declare it at security. Baby food and milk for infants are exempt in reasonable quantities for the flight. Duty-free liquids bought after security are allowed onward, but only in the sealed tamper-evident bag with the receipt, and only if your connection does not require you to pass through security again. A duty-free bottle bought in one airport and carried through a second security check without the sealed bag is a bottle you will lose.

Solid alternatives remove the problem entirely. Solid shampoo bars, solid deodorant, and bar soap are not liquids and do not count toward the limit, which is why experienced travelers pack them for trips through strict airports. Travel-size containers, decanted from full-size products at home, are the other solution: a set of labeled 100ml bottles costs a few dollars and lasts for years of trips. The goal is not to beat the rule. It is to make security a thirty-second step instead of a ten-minute bag search.

Before you fly, check the airport's own website for the current rule at your departure airport, because the situation changes every few months as scanners are installed. The UK's Civil Aviation Authority and the EU's aviation safety pages publish the current status, and most airports state their rule on their security page. Pack to the strictest rule, keep the bag accessible, and the liquid question stops being a question at all.

Connecting flights deserve special attention, because the liquid rule applies at every security checkpoint, not just the first one. A bottle bought duty-free after security in one airport can be confiscated at the next airport if that connection forces you through security again and the sealed bag is opened or missing. If your itinerary has a connection in a strict airport, keep duty-free purchases sealed, keep the receipt, and leave enough time to repack if needed. The safest souvenir is the one you buy at your final departure airport.