The short answer: there are four ways to secure a shipping container door. A padlock, a lockbox over the door handles, a bolt or cable seal, or a lock mounted inside the container. Three of the four hang on the outside. The right one depends on what the container does all day and who is trying to get in.
What are the main shipping container lock types?#
Here is the field, from simplest to least visible.
| Type | Where it sits | What it does | How it usually fails | Reusable? |
|---|---|---|---|---|
| Padlock | Outside, on the door bars or hasp | Keeps casual access out | Shackle cut with bolt cutters. A shrouded or disc padlock hides the shackle but can still be ground or pried. | Yes |
| Lockbox | Outside, enclosing the door handles | Blocks access to the handles and the lock | Steel enclosure can be ground, pried or cut away. Still a visible target. | Yes |
| Bolt or cable seal | Outside, through the door hardware | Shows tampering after the fact | Cut and replaced. A seal records a break-in, it does not prevent one. | No, cut off each trip |
| Internal lock | Inside the container | Holds the doors shut from within | No external hardware to attack. Defeating it means breaking through the container. | Yes |
General comparison. Products within each type vary, so check the specs of any model you buy.
Why do external locks get defeated?#
Because the thief can see them. A padlock or lockbox tells anyone who sees it exactly what to cut. Bolt cutters, angle grinders and pry bars all work on hardware that sits outside the door, and a thief working a parked container at night has time.
Better hardware slows that down. It does not change the fact that the target is exposed. That matters because most cargo theft is a parked-unit problem. Overhaul found pilferage, where thieves take part of a load from a parked trailer or container, was 46% of reported incidents in the second quarter of 2026. See the cargo theft statistics for the full breakdown.
Is a bolt seal a lock?#
No. A seal is a tamper indicator. If it is broken or missing when the container arrives, you know someone opened the doors. That is useful for a claim and for chain of custody, and for some customs and supply chain security programs it is required. It does not keep anyone out.
If you ship under a program like C-TPAT, check what it requires for loaded containers. Mechanical seals that meet ISO 17712 are the usual standard. A lock does not replace that seal. The two do different jobs, so the question is what to pair with the seal to stop the break-in in the first place. Keep your ISO 17712 seal for compliance and add VaultX for prevention. We compare the costs in reusable locks vs. single-use bolt seals.
How does an internal container lock work?#
VaultX is an internal lock. It mounts inside the container using the container's existing interior lashing rings and draws the doors shut from within. You lock and unlock it with a wireless remote or the Bluetooth app. It installs in under five minutes with minimal modification and it is reusable on every trip.
Because nothing locks on the outside, there is no lock to cut, grind, pick or pry. VaultX holds about 1.2 metric tons (2,600 lb) in container mode. It ran more than 1,000 times on a high theft rail lane in a year long field trial, and to date no VaultX lock has been defeated or broken into.
It is built to prevent a break-in, not to report one. GPS trackers and smart seals tell you after the doors have opened. VaultX is there to keep them shut.
How do you choose a container lock?#
Start with how the container is used, then work down this list.
- Does it sit still or move? A storage container on a lot has different risks than freight that rides a chassis and waits in drop yards.
- What is inside? High value or easy to resell cargo draws organized theft. Food and beverage is the most stolen by count.
- How many units? One container can live with a padlock and a key. A fleet needs something fast to apply and release, and a lock that is reused rather than replaced.
- Who has to open it? Consider the people at the other end. Keys and codes are a weak point when they travel by text or sit in an envelope.
- What does your program or insurer require? Read the policy. Many exclude unsecured or unattended units.
Not sure which fits your equipment? Schedule a VaultX demo and see it installed and released on a real container.
Frequently asked questions#
What is the best lock for a shipping container?
It depends on how the container is used. For a stationary storage container, a shrouded or disc padlock or a lockbox is common. For freight that moves and sits in yards, an internal lock removes the exposed hardware thieves target. If you need tamper evidence for a supply chain program, add a seal.
Can bolt cutters cut a container padlock?
A standard padlock shackle, yes. Shrouded and disc padlocks protect the shackle, but they are still outside the door and can be attacked with grinders and pry tools.
Do I need a bolt seal and a lock?
They do different jobs. A seal shows tampering. A lock resists entry. If a customs or supply chain program requires a seal, you keep it and add a lock.
What is an internal container lock?
A lock mounted inside the container that holds the doors shut from within. VaultX anchors to the container's interior lashing rings, locks and unlocks by remote or Bluetooth app, and installs in under five minutes.
How is VaultX different from a lockbox?
A lockbox is an enclosure over the door handles, so it sits outside and can be attacked. VaultX is inside the container with nothing external to cut or pry.