Checked against the Tokyo Metropolitan Police Department’s official page on 3 September 2026. Procedures can vary slightly by prefecture, so if you’re outside Tokyo, the one thing worth confirming locally is which police division handles lost-property reports in that area.

Setting a phone down on a train seat, a café table, or a taxi seat for just a second is all it takes. If it happens to you in Japan, don’t panic — Japan’s lost-property system is genuinely good at reuniting people with their things, and the process for reporting a missing phone is simple. There’s just one detail that catches travelers off guard, and it’s worth knowing before you actually need it.

Police need a way to call you back, and it has to be a Japanese number

The Tokyo Metropolitan Police Department’s own English-language guidance for people who’ve lost something is direct about this: when you file a report, you’re asked to provide a Japanese phone number so the police can contact you if your item turns up, “as a rule, they do not call internationally.” No local number, no callback — you’d need to return to the police station in person a few days later and ask whether anything has come in.

For most lost items, that’s a minor inconvenience. For a lost phone, it’s a real problem, since the phone is usually the thing you’d normally use to receive that call in the first place.

What actually works: borrow a number that reaches you

The fix is simpler than it sounds. Any Japan-based number that someone can actually answer for you works — a travel companion’s Japanese SIM or eSIM number, your hotel’s front desk (many are used to holding messages for guests), or a second device you’re still carrying. If you’re traveling with an eSIM that includes a Japanese phone number, that number is exactly the kind of contact detail the police are asking for, and giving it up front avoids the trip back to the station just to ask “did anything come in?”

Bring a filled-in Lost and Found form if you can — the police site has one available in advance — and go to the nearest police box (koban) or police station in person; reports by email aren’t accepted.

Suspend the line before you file the report, not after

Filing the lost-property report doesn’t do anything to stop someone else from using your line in the meantime, so it’s worth doing this first, not second. Contact your carrier directly to suspend service — SoftBank’s own English support page, for example, tells lost-phone customers to call their customer service line immediately to have the line temporarily suspended, and separately walks through locking mobile-payment (Osaifu Keitai) functions if your phone had them enabled. The same logic applies whichever provider issued your SIM or eSIM: a suspended line can’t be used to run up charges or intercept your text-based verification codes while you sort everything else out.

If it was stolen, not just lost, go straight to the nearest police station

A lost-property report and a theft report aren’t quite the same track. If you believe the phone was taken rather than simply left behind, report it as a theft at the nearest police station or call 110 — you’ll typically get a report reference on the spot rather than waiting for police to track you down later, which sidesteps the callback problem entirely.

How Travel AI Rescue helps

Travel AI Rescue keeps Japan’s police non-emergency line and your carrier’s support contacts one tap away, with the country code already attached, so you’re not searching for a number the moment you realize the phone is gone. It can display a Japanese-language card explaining exactly what happened — “my phone was stolen,” for instance — so station staff understand you immediately even without shared language. And above all, it keeps your travel documents and key numbers stored and readable on the device, so you can still pull up a passport number or booking reference from a borrowed phone or laptop with zero signal. It works differently from a staffed help desk, and it’s with you around the clock — a bridge that gets you to the right window with the right information already prepared. (Whether an item is returned, and how a report is processed, is decided by the police under their own procedures, not by Travel AI Rescue.)

Sources

• Tokyo Metropolitan Police Department, “If you’ve lost something.” https://www.keishicho.metro.tokyo.lg.jp/multilingual/english/finding_services/lost_and_found/lost_something.html (accessed 3 September 2026).
• SoftBank Corp., “Stolen / Lost Handsets.” https://www.softbank.jp/en/mobile/support/lost/ (accessed 3 September 2026).