If you intend to use your mobile frequently while abroad, consider the following options:

• Some mobile services offer international traveller services giving cheaper calls abroad in return for a monthly fee. Check with your network provider what the costs are and how long you would be committed to paying for the service.
• It is usually cheaper to use an alternative SIM card in your phone. A SIM card is a small card that lets the phone work on a particular mobile network. It can easily be swapped around in your phone. SIM cards for foreign networks can be bought abroad (for example, at international airports and holiday destinations) or (for some European countries) from some UK retailers. Find out if the alternative SIM cards will expire after a fixed time. Also ask your network provider whether it has locked your phone against use with a different SIM card, and what, if anything, it will charge to unlock the phone.
  
• You should be able to rent a mobile telephone handset for the duration of your stay from most mobile telephone companies in the country you are visiting.
  
• If you are particularly concerned about coverage or call quality you may be able to select a particular network for international roaming. Ask your network provider whether it offers a choice of networks and how you can change between them.
• If you are using your own network provider's pre-paid mobile international roaming service, make sure you know how to use your credit card to top up your calling credit before you leave, or take extra vouchers, as they may be hard to obtain abroad.
• Ask your network provider what you have to dial to use international roaming. This may not be as simple as just using the 0044 international prefix for the UK. In Portugal and Madeira you should be fine by prefixing the phone number you want to call back home with the 0044 but dropping any "0"s before the area code of the region you are calling in the UK.
• Pre-programme into your mobile the telephone number of the nearest British Embassy, High Commission, or Consulate in the country you are visiting.
• Do the same with the telephone number of your hotel and tour representative. If you are using an alternative SIM card whilst abroad you may have to programme the information in after you have inserted the alternative SIM card (as some phones record the phone numbers in the SIM card rather than the phone).
• Familiarise yourself with your mobile's voicemail retrieval system. Voicemail can be difficult to access while abroad, and you should ask your mobile network provider if this is not clear.
• Take an electrical adaptor for the charger plug, to keep your mobile telephone fully charged while you are abroad.
• Make a note of your mobile's serial number (also known as the IMEI number), your mobile telephone number and the telephone number of your operator's customer services (including UK dialling code).  Keep them with you in a safe place, separate from your mobile. If your phone is stolen you will be able to contact the network operator in the UK and request that they block your phone and/or SIM card. You may need to provide additional information in order to get the phone blocked, such as a password. Contact your operator for details of how they deal with stolen phones before you leave to ensure that you take sufficient information abroad to enable you to block the phone if it is stolen.