It’s a simple truth of modern, globally connected life: whenever you go overseas, your mobile-phone company has you over a barrel. Not only do the rates for phoning home skyrocket — nudging £2 a minute.for some countries — but you also pay up to £1.50 to receive a call while you are away. In fact, if you are in Australia and a caller tries to reach you five times but fails, and doesn’t even leave a message, that’s up to £12 clocked up.

These calamitous fees are known as roaming charges, and they mean that you pay two phone companies for one call — your network pockets the cost of the international call to home, then a local operator takes the cost of a local call within the country, plus high mark-ups to boot. In fact, the European Regulators Group (made up of 32 European regulatory bodies) produced a damning report at the end of May, which concluded that roaming “charges are very high, and without clear justification”.

It could take years for the findings to bite, but, in the meantime, there are ways to beat the charges. Here is our complete guide to using a mobile overseas — and when not to use one.

Will my mobile work overseas?

The answer is probably yes, as a standard dual-band handset can be used in almost 200 countries. The USA and Canada are exceptions, though, as they both require a tri-band phone, as do some 20 countries in Latin America and the Caribbean, including Peru, the Dominican Republic and
Mexico. If you are likely to be visiting North America regularly, consider a tri-band handset when you next upgrade.

If you are going to the States but don’t have a tri-band mobile, Cellhire (0800 610610, www.cellhire.co.uk) can rent you one for £18 a week (plus £350 deposit and £18 delivery and collection). This option means you can use your current Sim card and thus keep your existing number.

What should I do before going away?

If you pay your bills monthly, you’ll have to enable your phone for roaming. This is free and takes a few moments to do — just call your network provider. Plan in advance, though, as it can take up to 14 days to process — and remember, you can’t do it from abroad. Pay-as-you-go (PAYG) phones are usually pre-enabled.

In some countries, you won’t be able to access your voicemail without a personal identification number (Pin), so any messages will go unheard until you arrive home. Contact your network provider to set one up.

Also, check your phone’s address book and, in the case of UK numbers, delete the first zero and then add +44 to each one. If you leave phone codes in the format of 01332, for example, the phone will not be able to dial them from the address book. Some networks have a nifty tool that can automatically add the prefixes for you —
a mobile-phone shop can help.

If you are a PAYG customer, you should top up your phone before going away, or register credit or debit cards with your provider before leaving, so that you can then top up from overseas. If you forget, some networks have local top-up vouchers that can be purchased abroad — for example, Vodafone sells these in 21 countries, including Spain, France and Australia. Simply buy the voucher, then top up your account using the unique number on the voucher.

How much does it cost to make and receive calls abroad?

The exact amount varies from network to network and from country to country, but you can find tariff information on your network provider’s website or by giving them a call. For example, O2 charges £1.37 per minute to make a call from the USA, but Vodafone charges £1.49. Receive a call with Orange in Spain and you’ll pay 30p per minute; with O2 the call will cost 94p.

In general, PAYG customers will be charged more for all overseas calls than customers who pay monthly. For example, with Virgin Mobile, the per-minute PAYG call rate from Kenya is £1.70, while the pay-monthly rate is £1. Similarly for PAYG customers, receiving a call there costs 30p per minute more and sending a text costs 10p extra.

Also, a pay-monthly contract means that you can use your phone in more countries — 155 countries for Virgin Mobile pay-monthly customers, as opposed to 40 for those on PAYG.

How can I minimise roaming charges?