Will Your Android Phone Work With a Japan SIM Card? A 3-Minute Check
CDJapan Rental SIM cards and eSIMs run on the docomo network. Android models vary far more than iPhones do, so run these three checks before you order.
1. Is your phone carrier-unlocked?
A phone bought outright or SIM-free is normally unlocked. A phone that came with a contract or an instalment plan often is not.
Search your settings for SIM lock, Network unlock or SIM card status — the wording differs by brand, and some phones do not show it at all. The reliable answer comes from the carrier you bought it from, and unlocking can take a few days, so ask before you fly.
2. Find your exact model number
Go to Settings → About phone → Model number. It is also printed on the back of many devices or on the box.
The brand and series name is not enough. The same phone is sold as several different models for different regions, and they do not all support the same frequencies — so you need the full string that follows the name, such as SM-S921B or 2201123G.
3. Check that model against Japan's frequency bands
Search for your model number plus the word "specifications", ideally on the manufacturer's own site, and find the LTE and 5G bands it supports.
| Band | Why it matters |
|---|---|
| LTE Band 1 (2100MHz) | The main band. Essential — without it you will struggle everywhere. |
| LTE Band 19 (800MHz) | Reaches indoors, into suburbs and mountain areas. Strongly recommended. |
| LTE Band 3 / 21 / 42 | Extra speed and capacity in big cities. Nice to have. |
| 5G n78 / n79 | Needed for 5G speeds. Without them you still get 4G LTE. |
Band 19 is the one overseas models most often leave out. A phone with Band 1 but no Band 19 still works in cities; expect weaker signal in rural areas and inside some buildings.
4G LTE is now the minimum: Japan switched off its last 3G network in March 2026, so a 3G-only handset cannot connect at all. Our SIM is data-only, so you do not need to worry about VoLTE support for calls.
Also check the SIM slot
- Size: nothing to choose. Our physical SIM is a multi-cut card covering standard, micro and nano.
- eSIM-only models: a few newer Android phones have no card slot. If yours doesn't, order an eSIM instead. To confirm eSIM support, dial *#06# and look for an EID number.
- Dual SIM: if one slot is shared with the microSD card, you may have to remove the memory card to use ours.
One more thing to know: on Android you enter the APN settings manually after inserting the SIM. Instructions come with your order.
Not confident? Add SIM insurance when you order
Our prepaid SIM product page offers optional insurance for ¥880. If the SIM turns out not to work in your phone, contact us within 2 days of the pickup date and you get a full refund of the SIM price, minus the ¥880 itself. Add it at the time you order.
Still not sure? Rent pocket WiFi instead
A pocket WiFi router works with any Wi-Fi device — your phone, a laptop, a tablet, and your travel companions' phones too. No bands to look up, no carrier lock, no APN.
