When a phone is turned on abroad, it connects to a local operator's cell tower. This connection record lets the operator respond with whether a phone number is roaming and in which country.
The phone is connected to a cell tower in Taiwan. The operator's response is “not roaming.”
The phone is connected to a cell tower in Japan. The operator's response is “roaming,” with the country included.
The IP location shows Japan, but the phone is connected to a cell tower in Taiwan. The operator's response is “not roaming.”
A and CDifferent IP locations, same operator response: both phones are connected to cell towers in Taiwan.
B and CBoth IP locations are in Japan, but the operator's response shows who is actually abroad.
Device Roaming Status: How it works
- Check inWhen a phone is turned on, it registers with a nearby cell tower, so the operator network knows which network it is connected to.
- ReportWhen you are abroad, the local operator network reports the registration information to your home operator.
- ResponseThe service provider queries using the phone number. The operator responds with the roaming status, country, and status update time.
Device Roaming Status: API spec
POST /retrievephoneNumber| Response fields | Meaning | Example |
|---|---|---|
| roaming | Whether the device is roaming | true |
| countryCode | Mobile country code (MCC) of the current country | 440 (Japan) |
| countryName | Country codes corresponding to the mobile country code, shown as a list | ["JP"] |
| lastStatusTime | Time the roaming status was last updated | 2026-10-13T10:41:00Z |
Responses for three scenarios (excerpts)
falseNot roaming2026-10-14T10:41:00ZStatus update timetrueRoaming440Japan's mobile country code (MCC)["JP"]Country code: Japan2026-10-14T10:41:00ZStatus update timefalseNot roaming2026-10-14T10:41:00ZStatus update timeSpec source: CAMARA DeviceRoamingStatus r1.2 (Device Roaming Status v1.1.0, Subscriptions v0.8.0)
Device Roaming Status: GSMA use cases
Territory restrictions for content
Problem to solveUses roaming status and the current country to restrict content access in regions without a license.
Device Roaming Status's roleChecks whether the user is roaming and in which country.
GSMA source ↗Passenger Experience
Problem to solveMeets passengers’ varied needs to improve their travel experience.
Device Roaming Status's roleChecks whether a passenger is roaming, for example to meet content licensing requirements.
Used together: Location Retrieval, Quality on Demand, Carrier Billing
GSMA source ↗Sources: GSMA Open Gateway Use Case Library and API Descriptions (accessed 2026-10-14). Descriptions are summaries.