VoIP provider Truphone has revealed plans to offer international travellers a single mobile phone SIM chip allowing local-rate calls when travelling in a range of countries.

Called Truphone Local Anywhere, subscribers with the company's software loaded on supported handsets will be able to roam without having to worry about expensive and widely varying tariffs as they move from country to country and between network providers.

Call rates were not detailed by the company in its GSMA Mobile World Congress release, but are likely to be in line with the company's current price structure, which would vary according to the domestic local rate for that mobile. Typically, this means a flat-rate local mobile call using GSM in the location being called from, with as much of the call then being routed across the Internet using Truphone's servers.

In addition, the company claims that Truphone Local Anywhere will chop mobile roaming charges - a major complaint for users of conventional mobile networks - by up to 80 percent.

Separately, the company has a service that depends on using Wi-Fi for the first leg of the call, completing it without using GSM at all. Call rates for this Internet-only VoIP service currently range from 5 US cents per minute (3.5 pence) to phone landlines while in France, or 25 US cents (17.5 pence) to a mobile.

"Until now, the only way to avoid the massive cost of mobile roaming is to carry multiple phones and multiple SIM cards, one for each country you frequent," said Truphone CEO Geraldine Wilson. "This means juggling multiple devices and phone numbers to avoid paying the high roaming rates traditionally associated with travel.

"Now these internationalists can enjoy all the benefits of home wherever they may be," she said.
Other benefits of the service include low-cost dialing between countries while roaming, the use of virtual numbers so that users can appear to be ‘in' the country in which they are roaming, and cheap calls to other Truphone users using the same service.

Truphone is available as a free download for an expanding of platforms, including Nokia/Symbian, Apple's iPhone, the BlackBerry and, more recently, Google's G1 Android.

A small catch with the new Local Anywhere service is that it isn't scheduled to start until "later this year", so interested users will have to hang on for while yet.