Heathrow liquids rules: the 2 litre limit and the exemptions

The rule at every Heathrow security lane is the same since 24 January 2026:

• Liquids, gels, pastes and aerosols up to 2 litresper container in cabin baggage. No overall cap on the number of containers.
• No clear plastic bag required. Liquids sit loose inside the cabin bag.
• Laptops, tablets and other large electronics stay in the bag for screening. The CT scanner sees through the case.
• The rule is identical in the standard lane and Fast Track at Heathrow. Paying for Fast Track buys a shorter queue, not a different ruleset.
• All four operating terminals (T2, T3, T4, T5) run the same rule. There is no terminal carve-out.

The change followed the £1 billion next-generation CT scanner rollout. Heathrow was the first major global airport to fully scrap the 100ml limit. For the queue side of the experience (typical waits, Fast Track timing, peak windows), see current security wait times at Heathrow. For the airline-side limits on the bag itself (size, weight, count), see airline hand luggage allowances and the two-bag policy at security.

Heathrow's rule of thumb, taken directly from the airport's own page: if it spreads, smears, pours or sprays, it is a liquid. That sweeps in the obvious cases (water, fizzy drinks, perfume, shampoo, sunscreen, contact lens solution, mascara, lip gloss, toothpaste, deodorant aerosols) and the less obvious cases people forget about: yogurt, honey, jam, peanut butter, hummus, soup, soft cheese, soft custard, pâté.

Anything in solid form (a bar of soap, a stick deodorant, a solid perfume, a chocolate bar, hard cheese, ground coffee, dry pasta, biscuits) is not a liquid and does not count against the 2 litre rule. Spray cans count as liquid even if the contents are not technically liquid because the propellant is. The 2 litre limit is per container, not per item: a 250ml bottle of perfume next to a 500ml bottle of moisturiser is two containers, each comfortably inside the limit.

Three categories of liquid are exempt from the 2 litre limit at Heathrow security. Each has its own conditions and the conditions matter.

Liquid medication

Prescription and essential over-the-counter liquid medication can travel above the 2 litre limit, but only in the quantity needed during the flight, and you must have documentary proof on hand: a prescription, a doctor's letter, or the original packaging with the patient's name. Insulin, liquid painkillers, asthma inhalers (technically aerosols), eye drops, and saline solutions all qualify when the criteria are met. Without documentary proof, the standard 2 litre rule applies.

Baby food, formula, sterilised water

Prepared baby milk (formula), sterilised water for baby formula, and baby food (jars, pouches, finger food in liquid form) are fully exempt from any liquid limit when travelling with the infant they are for. Containers may be opened and tested at security, so allow a couple of extra minutes at the lane. The allowance covers what the infant needs for the journey; security officers can challenge volumes that look excessive.

Expressed breast milk

Expressed breast milk has its own allowance, and the wording matters. It can travel up to 2 litres per container with no cap on the number of containers, including when travelling without the infant. Formula milk does not share that no-infant allowance: without the baby present, formula falls under the standard 2 litre per container limit alongside everything else. Expressed breast milk must be in liquid form, not frozen, in individual containers up to 2 litres each. For the wider family-facilities picture (Stay & Play zones, family security lanes, Boots pre-order for formula), see the travelling with children at Heathrow page.

This is the section most readers need and most other sites skip. The 2 litre rule applies on the Heathrow security pass. The return leg through a different airport runs that airport's rules.

As of mid-2026, several UK airports (Manchester, Stansted and Luton among them) still operate the 100ml limit. Outside the UK, most major European, North American, Middle Eastern and Asian airports also still enforce 100ml. The reader returning from one of those airports has to pack to its rules, not to Heathrow's.

The practical consequences:

• A 200ml bottle of factor-50 sunscreen bought at home survives the Heathrow outbound but not the foreign return.
• A litre of duty-free spirits bought airside at Heathrow on departure does not clear security at a 100ml airport on the way back, unless it is sealed in a Security Tamper Evident Bag (STEB) at the connection airport.
• A 250ml moisturiser bought duty-free at a 100ml airport on the way back has to fit that airport's rules, which usually means buying after security in a sealed STEB.

The safest planning rule is to pack outbound and return separately. Outbound from Heathrow you have the 2 litres. Return to Heathrow from a 100ml airport you have 100ml per container in a clear bag, regardless of what Heathrow itself allows. The underlying UK position is on gov.uk hand luggage restrictions, which also lists the UK airports that have completed the upgrade.

Duty-free liquids bought airside at Heathrow can travel inside the cabin without restriction on a direct flight. The receipt at the till proves the purchase was airside and the till bag is sufficient packaging for the journey.

For a connecting flight at any onward airport, the duty-free liquid must be sealed in a Security Tamper Evident Bag (STEB) with the receipt visible inside the bag and the bag unopened. Heathrow stores supply the STEB at the till on request when the flight is a connection. The STEB is the international standard for airside duty-free in transit; without it, the onward airport treats the bottle as a standard cabin liquid and applies whatever rule it operates (which, at a 100ml airport, means the bottle is binned).

If you need formula, sterilised water or other baby liquids airside at Heathrow, Boots branches in every terminal stock the standard products. The wider Heathrow Reserve & Collect service (run through boutique.heathrow.com) covers beauty, fragrance, spirits and accessories from any participating store, with dedicated collection counters in the T2 and T5 departure lounges. The minimum lead time is 24 hours before the flight and the cut-off is 30 minutes before scheduled departure. Heathrow duty free shopping covers the platform in full.

One US-specific rule sits on top of the standard liquid limits. Passengers flying to the United States from Heathrow cannot carry powders or powder-like substances over 350ml or 350g (about the size of a drinks can) in cabin baggage. The rule covers protein powder, ground coffee, loose tea, cooking spices, powdered cosmetics, talc, and bulk supplements. Containers over the limit are pulled aside at the security check.

Three categories are exempt but still subject to further checks: medical powders, baby powders, and human ashes. For these, declare the item at the start of the security screening and carry supporting documentation where applicable (a prescription label for medical powders, a certificate from the funeral director or crematorium for human ashes).

The rule applies only to US-bound flights. It does not apply to Heathrow departures to other long-haul destinations unless the operating airline imposes its own version. The simplest planning rule: pack powders over 350g in hold baggage when the flight is to the US. The CT scanner can still confuse a large bulk of powder with prohibited material, so even on non-US flights, hold baggage is the easier route for anything substantial.

Vacuum flasks (Stanley, Thermos, Yeti, Chilly's, any double-walled insulated bottle) must be empty at the security lane. The flask itself is fine to carry; the contents are not. The double-walled insulation that keeps the drink hot or cold also blocks the CT scanner beam, so a full flask is pulled aside for a manual check and slows everyone behind in the queue.

Empty the flask before joining the queue (most terminals have water-bottle filling stations and bins near the security entrance) and refill at a fountain or shop after security. The exception does not apply to ordinary single-wall water bottles, which can sit empty in the bag through the scanner without comment.

Anything over 2 litres in a single container, or any item the officer judges to be in non-permitted form, is confiscated at the checkpoint. There is no refund. Amnesty bins next to the lane hold the discarded items; once binned, an item is not coming back.

If the item is valuable (a full-size bottle of expensive perfume bought on a previous trip, a litre of single malt whisky, a 500ml jar of speciality honey), the better moves are made before reaching security: repack into hold baggage if you have a hold bag, post the item home from the landside Royal Mail counter (T2 and T5 have one), or hand it to a non-flying companion. For the live picture at the checkpoint itself and the typical queue length when you decide to repack, see how long the queue is at Heathrow security. The wider departure flow, including check-in cut-offs and gate timing, sits on live departures at Heathrow.