Data comes first — translation and the camera depend on it. Here is how to get online, and what still works when you have none.
📶 Not connecting? Check these four
1) Turn airplane mode on, then off again. 2) Check that data roaming is ON — most eSIM trouble is exactly this. 3) If your phone holds two SIMs, check that mobile data is set to the Japanese line, not your home one. 4) Restart the phone. If it still will not connect, contact the company you bought it from — they can see the state of your line.
🛬 Three ways to get online
An eSIM bought before your trip (set it up before you fly, switch to it after you land) · a SIM or pocket Wi-Fi from a counter in the arrivals hall · free Wi-Fi. Availability and plans change, so check the seller’s official page.
📡 Free Wi-Fi, honestly
Convenience stores, stations, cafés and most hotels have free Wi-Fi. Some ask you to register with an email address first — which is hard to do with no signal, so register at the airport while you still have Wi-Fi. On public Wi-Fi, do not enter card numbers or passwords.
🆘 110 and 119 without data
You do not need mobile data to call 110 (police) or 119 (ambulance and fire) — a voice signal is enough, so they work even when your data has run out. ★ But in Japan a handset with no SIM usually cannot place an emergency call. If your phone cannot call, use a payphone (emergency calls are free — no coins or card needed; on older payphones, press the red button first) or ask someone at a shop or station to call for you. This app’s Emergency screen also opens with no signal, once you have opened it once.
📵 What works with no signal
Saved phrases, the emergency phrases, the local know-how and the arrival guide all work with no connection. Translation and reading signs with the camera do need one. So save the phrases you may need while you are still online.
🔌 A flat battery is the same as no signal
Convenience stores and electronics shops sell power banks, and many cafés and stations have outlets. Outlets in Japan are the flat two-pin type at 100V — check that your charger accepts it.
Plans, prices, coverage and settings differ by carrier and by phone, and they change. This is general guidance — for your own line, ask the company you bought the SIM or eSIM from, or a counter at the airport.