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Travel Guide

Airport Security & Carry-On Rules Explained

Breeze through security by knowing the rules

By Daniel HartReviewed
5 min read

Airport security is smoother when you know the rules in advance. While details vary by country, the core principles are widely shared. Here's what to know to pack right and move through quickly.

The Liquids Rule

The widely used rule limits carry-on liquids to containers of 100ml (3.4 oz) or less, all fitting in a single clear, resealable bag of about one litre. This covers liquids, gels, pastes, and aerosols — including things like toothpaste and sunscreen. Some airports are rolling out new scanners that relax this, but assume the standard rule unless told otherwise.

Electronics

Larger electronics like laptops and tablets usually need to come out of your bag for screening (again, newer scanners are changing this). Keep them accessible near the top of your bag to save time.

What You Can't Bring

  • Sharp objects and tools over certain lengths in carry-on.
  • Liquids over 100ml in carry-on (pack them in checked bags).
  • Flammable items; certain batteries have specific rules.
  • Check country-specific restrictions for your departure point.

Speed Through Security

  • Have your liquids bag and electronics easily accessible.
  • Wear easily removable shoes and minimal metal.
  • Empty pockets into your bag before the queue.
  • Arrive early enough to avoid rushing.

TSA PreCheck, Global Entry & Fast-Track Lanes

Trusted-traveler programs let you skip the longest lines and keep shoes, belts, and laptops in place. In the US, TSA PreCheck covers domestic security lanes, while Global Entry adds expedited customs on international arrivals (and includes PreCheck). Many other countries run their own fast-track schemes — the UK has Registered Traveller, and the EU is rolling out its Entry/Exit System. If you fly more than a couple of times a year, the time saved usually justifies the modest application fee.

Traveling with Food, Medication & Special Items

Solid foods are generally fine in carry-on, but anything spreadable, pourable, or gel-like (yogurt, peanut butter, soup) counts as a liquid and must follow the 100ml rule. Medications are exempt from the liquids limit — bring them in reasonable quantities and declare them at the checkpoint if they exceed 100ml. Baby formula, breast milk, and juice for infants are also allowed in larger amounts. Powders over 350ml (about 12 oz) may need separate screening on some routes, so keep them accessible.

Frequently Asked Questions

The standard rule limits carry-on liquids to containers of 100ml (3.4 oz) or less, all fitting in one clear, resealable bag of about a litre. This includes gels, pastes, and aerosols like toothpaste and sunscreen. Pack larger liquids in checked bags. Some airports are introducing scanners that relax this.

Written by

Daniel Hart

Founder & Editor

Daniel Hart is the founder and editor of Travel and Time. An aeronautical engineer who spent two decades in aviation, he built the site’s flight-distance, route, and airport tools and oversees its research and accuracy. He has travelled widely across India over twenty years of work postings.

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