Many travelers assume that locking a carry-on is enough to keep their belongings safe. While a luggage lock can help deter casual theft, it’s only one part of protecting your bag during a trip. So, what kind of lock is actually worth using? Do TSA-approved locks make a difference? And is a suitcase with a built-in lock better than adding your own?
We’ll answer those questions in this post and explain what to look for when choosing the best carry-on luggage with lock, along with practical tips for keeping your belongings secure while traveling.
Yes — and if you’re in the market for a new bag, the lock should be part of the evaluation, not an afterthought.
The common assumption is that a carry-on stays with you, so it’s safe. On a perfect flight, that’s mostly true. But travel is full of moments that aren’t perfect:
Going back to the pen trick — this is also why the type of bag matters as much as the lock itself. A soft-shell bag with zipper pulls, even a locked one, still has a zipper coil that can be gapped without touching the lock. A hard-shell bag with a built-in latch and combination lock closes differently — the shell itself latches shut without a zipper coil, which removes that vulnerability at the structural level. It’s not about paranoia. It’s about understanding where the actual weak points are.
There are three locking options you’ll encounter on carry-on luggage: built-in combination locks, key locks, and TSA-approved clip-on padlocks. Here’s how they compare in practice:
1. Built-in combination locks use a 3-digit or 4-digit code set by you, integrated directly into the bag’s closure — either the zipper slider mechanism or, on hard-shell bags, the latch system. No extra hardware, no key to track, and resetting takes under a minute. On a hard-shell bag, a built-in lock also means the bag closes via a latch rather than a zipper track, which removes the pen-trick vulnerability entirely.
One thing worth mentioning on code selection: avoid 0-0-0, 1-2-3, and birth years. These are the first combinations any opportunistic thief tries. A random code that means something personal to you — a former area code, an old locker number — is far harder to guess than anything sequential.
Some higher-end soft-shell bags now feature a double-layer anti-theft zipper design, where a secondary fabric or seam layer conceals the zipper coil entirely — making the pen method significantly harder to execute even before the lock is engaged. It’s worth looking for if you prefer soft-side construction.
2. Key locks provide a solid mechanical barrier but carry a real travel risk: lose the key in a foreign city and you’re waiting on a locksmith or cutting the bag open yourself. I’ve seen this play out at airport terminals more than once. It derails the first few hours at a destination in the most preventable way imaginable.
3. TSA-approved clip-on padlocks are better than nothing, but they add external hardware that snags on conveyor belts, and on soft-shell bags they still leave the zipper coil exposed. On a checked bag they serve a purpose; on a carry-on, they’re a half-measure.
What about biometric or smart locks? Fingerprint-based biometric locks and Bluetooth-enabled smart locks do exist in the luggage accessories market, but neither is widely integrated into carry-on luggage at the bag level. They’re worth knowing about — and worth excluding from consideration for most travelers. Battery dependency, TSA compatibility gaps, and higher price points make them impractical as a primary carry-on security solution for now.
Recommendation: A built-in combination lock — ideally TSA-approved — on a hard-shell or semi-rigid carry-on is the most complete setup for most travelers. It closes the zipper vulnerability, eliminates key management, and handles inspection requirements in the same step.
TSA-approved locks use a master key system managed by the Transportation Security Administration, and they do what they claim: allow agents to inspect your bag without cutting or damaging the lock.
Most travelers only know one TSA-approved standard, but there are actually two. Travel Sentry uses a red diamond logo on the lock body and is the more widely recognized. Safe Skies uses a green-and-white logo and is less common but equally valid — both are recognized by TSA and by border agencies including Canada’s CATSA, Japan’s MLIT, South Korea’s KOCA, and a handful of other partner countries. If you’re evaluating a bag with a built-in TSA lock, it’s worth knowing which standard it uses so that you can identify the symbol during airport procedures.
In practice, the inspection process is quick. An agent opens your bag with the master key, checks what triggered the scan flag, relocks it, and returns it to the belt — typically two to three minutes. Your bag arrives intact, the lock re-engaged.
Here’s what most luggage brands won’t mention: the TSA master key system was publicly compromised in 2015. The Washington Post published photographs of the full master key set alongside a story on travel security — the images had been taken at a trade event — and within months, working copies had been produced from the publicly shared CAD and STL files and distributed online. Anyone with access to those files can replicate a master key.
This sounds worse than it is in practice. The typical opportunistic thief working a busy terminal is not carrying a 3D-printed TSA master key. That kind of preparation requires specific intent, not casual opportunity. TSA locks still reliably stop casual theft, which is the realistic threat in most airport environments.
The more useful takeaway is this: the zipper coil on a soft-shell bag is a bigger real-world vulnerability than the TSA lock system. A determined thief in an airport doesn’t need a master key if the bag has a fabric body and zipper pulls. Hard-shell construction eliminates that weakness, which is why the bag itself matters as much as the lock.
Other honest drawbacks:
The right answer depends on your routing.
Flying to or through the U.S.: A built-in TSA-approved combination lock is the practical standard. It eliminates the risk of a cut lock, requires no external hardware, and handles domestic and cross-border inspection requirements in one step.
Traveling entirely within Europe or Southeast Asia: TSA certification matters less because agents there won’t carry the master key regardless. What matters is the quality of the lock mechanism and — more importantly — the bag construction. A built-in combination lock on a hard-shell bag stops casual theft just as reliably as anywhere else, and the hard-shell eliminates the zipper coil vulnerability that soft bags carry everywhere.
For travelers routing through North American airports at any point, a built-in TSA-approved combination lock covers all scenarios without extra pieces to manage. That’s the combination worth looking for when you’re shopping.
One bag worth looking at if you want all of this sorted from the start is the Expandable Luggage from Foldable Space. It comes with a built-in TSA-approved combination lock — no padlock to source separately, no key to track. The hard-sided construction closes the zipper coil vulnerability that soft bags have, which matters more once you understand that threat properly.
