A backpack doesn’t strictly need a lock the way a hardside case commonly carries one, but adding a small TSA-recognized lock through the main compartment’s zip pulls is a low-cost way to add a real deterrent against casual opportunistic access, particularly relevant if the pack will be checked, left in shared accommodation, or stored in a public locker at some point during a trip.
For an anti-theft backpack specifically, lockable zip pulls are often built into the design already, clipping to a fixed point without needing a separate padlock — check whether this feature is already present before buying an additional lock that duplicates it.
For a backpack that never leaves the traveler’s direct possession or sight, a lock adds little practical value — the security benefit is specifically for situations where the bag is out of sight or being handled by others.
Check with your airline and read the label before you follow anything here. Lithium battery watt-hour limits, liquids allowances and lock policies differ by carrier and by country, and change over time — the figures published by the airline or security authority you are actually traveling with take precedence over anything written on this site. A power bank or spare battery is carried exactly as its manufacturer and your airline specify, never estimated. We report what is published — a watt-hour rating, a size limit, a lock's official recognition — and this site describes the equipment only: nothing here is a guarantee about what a specific checkpoint will allow on a specific day.
Last reviewed 26 August 2026