This Practice Note provides guidance on the rules applicable to UK mobile phones when they are used to roam outside of the UK. The regulation of roaming The term ‘roaming’ in relation to telecoms means the ability of a mobile phone network subscriber to use their device and continue to make and receive calls, send and receive data, use the internet, and access other communication services in another country outside of their home network’s geography. Roaming is made possible by agreements between customers’ home communication network operators and operators in other countries which enable users to connect to the foreign networks and ‘roam’ on them. In exchange for roaming rights, the communication network operators pay charges to each other. This surcharge is usually passed on by the home network operator to the subscriber. Roaming, especially when used for data connections, was historically unregulated, which often resulted in the network subscriber incurring significant costs. This was particularly the case if travellers had been unaware of their usage when travelling abroad. This resulted in users incurring ‘bill shock’ when faced