Pack liquids for every airport on your route

Use the most restrictive checkpoint you expect

Start with the airports where you will actually pass through security: departure, any connection requiring rescreening, and the return airport. Check their current official guidance. A new scanner at one terminal does not establish what another terminal or country will accept. UK government guidance explicitly tells travellers to check connecting and return airports.

For a simple packing plan, use containers and a liquids bag that meet all the ordinary limits you have confirmed along the route. If one airport permits larger containers, taking advantage of that allowance can still leave you with a problem at the next checkpoint. An item accepted yesterday is not proof of permission tomorrow.

Separate the container rule from the bag rule

At US TSA checkpoints, the ordinary carry-on rule is containers of 3.4 ounces or 100 millilitres or less in one quart-size clear bag per passenger. The size of each container and the combined bag are separate checks. A collection of small bottles does not create permission for unlimited additional bags.

Where a 100ml container limit applies, a half-empty 200ml bottle is still a 200ml container. Use a correctly sized bottle with a readable capacity marking. UK guidance confirms that part-full containers larger than the permitted size are still restricted. Do not estimate volume by squeezing a bottle or tell yourself that the remaining amount must be acceptable.

Do a bathroom-counter rehearsal

Put every liquid, gel, cream, paste and relevant aerosol you intend to carry on in one place. Include products scattered in the handbag, makeup pouch and camera bag. Ordinary toothpaste, sunscreen and lip gloss can be easier to forget than shampoo. Check unusual products against the screening authority’s item guidance rather than guessing from their packaging.

1. Choose the products you need during the journey and those that can travel in checked baggage if permitted.
2. Use suitable small containers for ordinary toiletries; do not decant medicines just to copy this packing method.
3. Close the liquids bag comfortably at home. If it cannot close, remove products or reduce their containers.
4. Place the bag where you can reach it without emptying your whole carry-on. Follow the checkpoint officer’s instructions about removing it.

Make room without evading the rules

Reduce duplication before buying special travel products. If two travellers already use the same product, decide whether one compliant container is enough for the trip. Take only the quantity you reasonably expect to use and account for the return. A solid product may be convenient, but verify its actual form and relevant restrictions rather than relying on the word “solid” in advertising.

If a specific skin product matters to you, test its travel container at home for leakage and label it clearly. Put a small piece of protective material around a fragile container without making screening unnecessarily difficult. This is packing advice, not a recommendation to alter a medicine or substitute a prescribed treatment.

Keep legitimate exceptions separate

Medically necessary liquids, baby feeding supplies and other exceptions require their own official check. TSA information permits medically necessary liquids above its ordinary size limit, with screening procedures. Do not discard essential medicine to fit the toiletries bag. Read the relevant authority’s instructions and tell screening staff when an exempt item needs separate handling.

Duty-free purchases also have conditions and can create problems during connections. Before buying a large bottle, ask whether your exact connection accepts it and what sealed packaging and receipt are required. A shop sale is not a guarantee of acceptance through every later checkpoint. Preserve the required packaging until the applicable rules allow it to be opened.

Decide what to do if something is rejected

Ask which rule applies and what legitimate options remain. Depending on time and airport facilities, you may be able to return landside, check an eligible item or leave it with someone. None of those options is guaranteed, and going back can jeopardise the flight. Decide whether the item is worth that risk before leaving the screening area.

Never split liquids into extra trays to hide them, as some Reddit replies suggest. The useful habit is to keep a short route checklist with the confirmed limits and date checked, then pack once for the whole journey. Before returning home, review the list again instead of assuming the outbound experience settled the question.