What is JAPAN roaming starting from April? Compatibility with iPhone and how to use it

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From April 1, 2026, each mobile carrier will start providing a service called JAPAN roaming.

JAPAN Roaming is a service jointly undertaken by domestic mobile carriers to secure a means of communication in emergencies.

This time, we will explain the mechanism and method of JAPAN roaming, and how to use JAPAN roaming.

What is JAPAN roaming?

JAPAN Roaming is a service that allows you to temporarily switch to another mobile operator’s equipment and secure a means of communication in the event that your mobile operator’s network becomes unavailable due to a large-scale disaster, etc.

The four mobile carriers that will start JAPAN roaming are NTT Docomo, au, Softbank, and Rakuten Mobile.

There are two types of JAPAN roaming: “Emergency call only method” and “Full roaming method”, and either method is provided depending on the situation of communication failure.

Emergency call only method

With the emergency call only method, you can only make calls to 110, 119, and 118, and cannot send SMS or data communications.

Additionally, your phone number and location information will not be sent to the recipient, and you will not be able to receive a call back.

Therefore, it is necessary to accurately convey the details of the report.

Full roaming method

Full roaming, on the other hand, allows voice calls, including emergency calls, as well as SMS and data communications.

However, data communication is limited to 300kbps for sending and receiving via 4G line only.

Ideally, it would be provided in full roaming mode.

However, depending on the situation of communication failure, it may not be possible to obtain the information necessary for full roaming, which makes it difficult to provide full roaming.

Therefore, it is provided in two ways.

iPhone compatibility status

Emergency call only method

When I checked each company’s website, I found that the emergency call only method was not available for all iPhones.

However, iPhone16e, iPhone17, iPhone17 Pro, iPhone17 Pro Max, and iPhone17e are scheduled to be updated around summer 2026.

It seems that this will be possible with an iOS update or carrier settings update.

Full roaming method

Full roaming support is available for Docomo and Softbank from iPhone 6.

SoftBank’s iPhone 6 to iPhone X do not allow “emergency calls with 184 or 186 added”.

au is available on iPhone 12, iPhone SE (2nd generation) and later.

Rakuten Mobile is available for iPhone 13, iPhone SE (3rd generation) and later.

These are based on the results of operation confirmation by each company, so there is a possibility that you can actually use them even if they are not available.

How to use JAPAN roaming on iPhone

From here we will explain how to use JAPAN roaming on your iPhone.

Please note that the usage is different depending on the emergency call only method and the full roaming method.

Emergency call only method

When using the emergency call only method, go to Settings → Mobile Communication → Network Selection → Turn off Auto and select one of the following:

“NTT DOCOMO” “DOCOMO” “44010”

“KDDI” “KDDI_50” “44050”

“SoftBank” “44020”

“Rakuten” “44011”

It will show that you are out of range, but you will continue to dial the emergency number until you are connected.

Make sure to choose a carrier that has not experienced communication problems due to the disaster.

When finished, turn “Auto” back on.

If you forget to turn “Auto” back on, you will not be able to communicate even after the communication failure has been resolved, so be sure to turn it back on.

Full roaming method

This is for automatically connecting to the JAPAN roaming provider in the event of a communication failure.

If it does not connect automatically, go to Settings → Mobile communications → Network selection → Turn off automatic and select a network that includes “JPN-ROAM”, “JpnRoam”, or a 5-digit number string that includes “4409”.

Please note that the network name is different for the emergency call only method and the full roaming method.

Can it be used with MVNO?

Even with MVNO operators, emergency calls, voice calls, and SMS are available in full roaming mode.

However, data communication is only supported by some MVNO operators.

You will need to check with your MVNO for details.

How to avoid relying on JAPAN roaming?

If you have an iPhone XS or later, you can insert two SIM cards with the Dual SIM feature.

We recommend that you use this dual SIM to use a carrier other than au as your main line and subscribe to povo as your sub line.

povo is a low-cost SIM with a basic fee of 0 yen and a system that charges you for communication amount when you want to use it.

For example, if you subscribe to Softbank as your main service and povo as a sub, when a communication problem occurs with SoftBank, you can simply switch to Povo and use the Internet without being affected by the communication problem, and it will be easier to obtain information about communication problems.

Please note that even if you set au as the main line and povo as the sub line, povo uses the au line, so it will be affected by communication failures, and as a result, you will not be able to use it with both SIMs.

The actual provision of JAPAN roaming seems to be determined after consultation in the event of a disaster, so it is possible that the network will be unavailable for several hours.

If you subscribe to povo as a sub-line, you can feel safe because you can switch immediately from the settings and use voice calls and the Internet.

Source: “JAPAN roaming” that supports communication in emergencies” – YouTube