According to Recommendation ITU-T D.97, international mobile roaming (IMR) is a service (voice, SMS/multimedia messaging service (MMS), data) that subscribers to post-paid or prepaid mobile services purchases from a mobile operator in their home country, that is, from the 'home operator'. It allows subscribers the convenience to continue to use their national mobile phone numbers to access voice, short message service (SMS), and data services while visiting another country, by accessing a mobile operator's network in the visited country, that is, the network of the 'visited operator' – with all arrangements made by their home operator.
IMR wholesale and retail rates are the prices charged for IMR service where:
a) IMR wholesale rates are the prices that the visited operator charges the home operator for allowing the home operator's subscriber to roam on the visited operator's network (in some cases referred to as inter-operator tariffs (IOTs)); and
b) IMR retail rates are the prices that the home operator charges its subscribers for usage of IMR services.
International mobile roaming issues (including charging, accounting and settlement mechanisms and roaming at border areas) are a subject of study under Question 7/3 of ITU-T Study Group 3 (SG3).
Cross-border connectivity is an increasing topic of relevance to certain developing regions in the world. The global economy is increasingly dependent on reliable, cost-effective, competitive and affordable mobile communications technology. International mobile roaming is a service that allows mobile users to continue to use their mobile phone or other mobile device to make and receive voice calls and text messages, browse the internet, and send and receive emails, while visiting another country. Roaming extends the coverage of the home operator's current, emerging, and other future services.
WTSA Resolution 88 (Rev. New Delhi, 2024), International mobile roaming,
resolves that ITU-T SG3 continues:
- to study the economic effects of IMR rates, including principles and methodologies for facilitating fair and reasonable IMR arrangements, and
- to study the roaming aspects of IoT/M2M services.
ITU-T SG3 is currently studying a number of work items under this topic of Question 7/3: find out more
here.
Watch a webinar by ITU-T SG3 experts on the completed and ongoing work of IMR:
here.
Relevant publications include:
