However, for travellers in many parts of the world, "roaming agreements" between international mobile phone networks mean it is now possible to use a mobile phone within many countries in Europe, the Middle East, South Africa and the Pacific Rim.
More and more mobile phone networks worldwide are operating on the same GSM digital frequency. In the UK, agreements by Cellnet and Vodaphone with foreign network providers have enabled their digital phone customers to make and receive calls in nearly 60 countries with the same phone and number. International roaming, as this is known, is more restricted for customers of Orange and One to One as these networks operate on a GSM frequency less widely used.
All customers with a GSM digital phone need do to activate its international roaming capability is gain clearance from their individual service provider, something which should be a formality.
This new-found freedom for mobile phones has resulted in many holidaymakers packing them with their travel guides and sun tan lotion. Cellnet's Dave Massey says: "In August last year, the number of calls from Spain was nearly 70 per cent higher than the monthly average across the year and in Portugal it was 50 per cent."
Travellers can also hire GSM digital phones from such outlets like Talkland Hire Solutions and Cell Hire. A week's phone hire within Europe from Talkland Hire Solutions will cost pounds 24.50, with calls back to the UK costing around pounds 2 per minute, depending on the network used.
One area where GSM digital phones are not compatible is North America. Anyone who wishes to use a mobile there will either have to buy or hire one. Talkland Hire Solutions will hire out a USA compatible mobile phone for a week for pounds 25 with calls charged at pounds 1.95 per minute.
Cellnet and Vodaphone offer digital customers a service for North America which lets them hire a phone and keep their existing number, with all charges invoiced on their usual monthly bill.
Being aware of call charges is a crucial factor. While international roaming is convenient, it can also be expensive, even when receiving calls.
Cellnet charges 50p per minute from the UK to Germany, Vodaphone costs 56p and Orange 49p, all excluding VAT. In the USA, an incoming call from the UK, excluding VAT, will cost 53p on Cellnet and 68p on Vodaphone.
Vodaphone's Libby Pritchard says: "A person abroad pays for the international leg of calls made from the UK. This is because it would be unfair for someone phoning up thinking you were in the UK having to pay for a call to somewhere like South Africa. To strike a balance, we recommend that the person diverts calls and picks up messages."
International roaming has its advantages. It allows people to save on the cost of using the hotel's own phone, where charges are often marked up two or three times.
Putting things into perspective, when you are spending anything from pounds 500 to pounds 1,000 on the annual holiday, what is another pounds 10-pounds 15 compared to the fun - and sense of cool - of speaking to a close friend or relative as you walk along the streets of New York or the beaches of Spain?
Cellnet: 0800 214000; Vodaphone: 0836 1191; Talkland Hire Solutions: 0171 229 4648