If you're visiting London from overseas, don't forget that the UK dialling code is +44 (which replaces the 0) and to check your own country's code before you travel.
Calls and texts
If you are travelling to London from abroad, using your mobile phone may cost you more than it does at home.
Roaming charges vary between countries, so make sure to check in with your mobile network before you travel.
If you're planning to stay in London for a significant period of time, consider buying a pay-as-you-go SIM card when you arrive. These are available from any mobile telephone shop and allow you to make calls and send text messages at the local rate.
Using the internet on your smartphone
Most Tube stations are wifi enabled. Visit the Transport for London website for information on how to connect.
If you're visiting from overseas, you could be charged extra to use a smartphone to browse the internet and receive emails while in London – check with your mobile phone provider before your trip.
To save money, turn off your data connection before you travel, then head to one of the many internet cafes or venues offering free wifi when you want to check your messages. Be aware that while some hotels provide free wifi, others will charge for this service.
You can also rent a pocket mobile wifi service with unlimited data during your trip.