What Happens If I Lose the Key to My Safe Deposit Box?

By The Penny Plan Editorial Team Published July 13, 2026 6 min read

The box is still there, the contents are still safe, but the key that opens it is nowhere to be found, and now there’s a decision about what to do next. It’s more common than it feels in the moment, and banks have a standard process for exactly this.

In a nutshell

A lost safe deposit box key usually means the bank has to drill the box open, since most boxes require two keys — the customer’s and the bank’s — and one missing key can’t simply be duplicated for security reasons. Drilling typically comes with a fee, and the box may need new locks installed afterward, which can add a replacement cost. Exact fees and procedures vary by bank.

Why banks can’t just cut a new key

Safe deposit box locks are designed so that no single party, not even the bank, can open a box alone. Because of that dual-key design, there’s no master key on file that the bank can use to make a replacement, and locksmiths generally can’t safely pick this style of lock without risking damage to the mechanism. Drilling becomes the standard fallback specifically because the security design that protects the box also prevents an easy workaround.

What the drilling process generally involves

What tends to reduce the cost or hassle

Reporting a lost key as soon as it’s noticed, rather than waiting, avoids paying rental fees on a box that may need replacement anyway if the loss goes unaddressed for a long stretch. Some banks offer a lower fee for a lost-key event covered under a rental agreement’s terms, so checking the original agreement is worth doing before assuming drilling is the only path or that it will cost a specific amount. This process is different from a bank drilling a box for reasons unrelated to a lost key, such as an unpaid rental fee, where the bank initiates the drilling rather than the box holder requesting it.

What to weigh going forward

After a box has been drilled and re-keyed, some people choose to continue using the same box, while others decide the ongoing cost and inconvenience of a safe deposit box isn’t worth it compared to other ways of storing important documents or valuables. That’s a personal call based on what’s stored, how often access is needed, and what a bank’s specific replacement fees look like. Keeping a small cushion set aside for unexpected costs like this one means a drilling fee doesn’t have to derail a monthly budget, and it’s a similar mindset to the record-keeping habits people build after documenting belongings for other reasons, like proving ownership after a loss.

Worth remembering

A lost safe deposit box key is inconvenient and typically comes with a drilling fee plus a re-keying cost, but it doesn’t put the contents of the box at risk, since the dual-key design is exactly what necessitates drilling instead of a quicker workaround. Checking with the specific bank about its process and fee structure is the most reliable way to know what to expect.