The 100ml Game: A Week of Summer Toiletries Through Carry-On Security

It's late May, the sunscreen shelves are fully stocked, and you've committed to flying with nothing but a cabin bag. Clothes compress, shoes squash, chargers slot into the gaps. Then you reach your wash bag and the whole plan stalls — because the one thing airport security cares about most is the one thing you can't fold smaller.

Liquids are the real reason carry-on-only travellers cave and check a bag in summer. They don't compress, they leak at altitude, and there's a hard limit on how many you can bring. Beat the liquids rule and you've usually beaten the whole checked-bag question. Here's how.

The rule, stated precisely

Across the EU and UK, the hand-luggage liquids rule has been steady for years:

• Every liquid, gel, cream, paste or aerosol goes in a container of 100ml or less.
• All those containers must fit inside one transparent, resealable bag of about 1 litre (roughly 20 by 20 cm).
• One bag per passenger, out of your luggage and ready to scan on its own.

Two details trip people up. First, it's the container size that counts, not how much is left inside: a 150ml bottle with a single splash in the bottom still gets pulled, because the bottle itself is bigger than 100ml. Second, the word liquid covers more than you'd guess.

Some airports have fitted new CT scanners that can, in principle, allow larger liquids and let you leave the bag packed. Coverage is patchy and the rules have flipped back and forth — in 2024 several UK and EU airports that had relaxed the limit put the 100ml cap back. Treat 100ml as the rule everywhere and treat anything more generous as a bonus. Check the airport's current policy before you fly, not at the belt. The same 100ml logic applies right across the EU, and the official EU luggage restrictions page is worth a glance if you're connecting through a hub you don't know.

What actually counts as a liquid

The restricted list is longer than drinks and shampoo:

• Toothpaste, and any gel or paste
• Deodorant, if it's roll-on, gel or spray
• Mascara, lip gloss, liquid foundation
• Sunscreen and aftersun — the big summer ones
• Moisturiser, hand sanitiser, contact-lens solution
• Anything squeezable, pourable or sprayable

Sunscreen is the summer villain. A proper week in strong sun can burn through 200ml or more, and a single tube is almost always bigger than 100ml. That one item can swallow half your liquids bag before you've packed anything else.

Go solid, and it stops counting

The cleanest fix is to take liquids out of the equation entirely. Solid toiletries aren't restricted, don't count toward your 1-litre bag, and can't leak over your clean shirts. The swaps that genuinely work:

A shampoo bar also outlasts the equivalent bottle by a wide margin, so it pays off twice: it clears security and it stretches further on a longer trip.

Decant the rest

For anything you can't or won't swap, shrink the container, not just the contents:

• Buy a few small refillable bottles of 50 to 100ml and fill them from your full-size products at home.
• Label them, so security can see at a glance what each one is.
• Keep the bag at the very top of your pack — it has to come out and sit visible in its own tray.

A 1-litre bag realistically holds six to nine small bottles, which is plenty for one person for a week once you've gone solid on the bulky items.

The exemptions worth knowing

A few things are allowed over 100ml, provided you handle them properly:

• Essential medicines, including liquid prescriptions, insulin and the like. Carry proof — a prescription or a doctor's letter — declare them at the checkpoint, and check the airport's rules in advance.
• Baby milk, formula and baby food when you're travelling with an infant, in reasonable quantities. Staff may ask to test a sample.
• Duty-free liquids bought airside are fine on a single, direct flight. The trap is connections: if you self-transfer or change planes, you clear security again, and a bottle over 100ml can be confiscated unless it's still sealed in its tamper-evident bag with the receipt inside — and even that sealed bag isn't honoured everywhere. If you're stitching your own layover together, don't buy the litre of gin until your final leg.

Build a summer kit that clears security in one pass

A concrete carry-on-only wash kit for a week in the sun:

1. Solid, no bag needed: shampoo bar, soap, deodorant stick, toothpaste tablets, and a sunscreen stick for your face.
2. Liquid, in containers of 100ml or less: one decant of body sunscreen to cover the first day, aftersun, insect repellent, and any prescription drops.
3. Bought on arrival: a full bottle of body sunscreen is cheaper and far easier to grab at a supermarket near your hotel than to smuggle through in tiny dribs. Budget five minutes for it on day one.

If you're travelling on the personal item alone — say a compression backpack sized to slide under the Ryanair seat in front of you — liquids are the one category that can blow the whole plan, because they refuse to squeeze smaller; going solid is exactly what buys the space back. You can see how we handle that at Ryanwear.

At the scanner, move fast

• Liquids bag out and in the tray before you reach the belt.
• Water bottle empty — full ones get pulled. Carry an empty one through and fill it at a fountain airside.
• Anything electronic bigger than a phone comes out too, unless the signage says otherwise.
• Unsure about a specific item? Check the airline's or airport's current policy rather than gambling at the front of a long queue.

The liquids rule feels like the tax you pay for packing light. It's really just a nudge toward better kit. Go solid where you can, decant what's left, buy the bulky stuff when you land, and that clear plastic bag stops being the thing that forces you to check a case. It becomes what it should be: a free personal item with room for your whole summer.