Apple has started selling its own brand of mobile internet SIM for Australians travelling overseas in a move that could make global roaming cheaper.

Apple SIM cards will be sold at its stores around Australia in the coming weeks. It gives buyers a chance to get cheaper data when using their iPad tablets in over 90 foreign countries such as New Zealand, the United States and the United Kingdom.

Apple and Google are the latest technology giants to sell self-branded phone and internet-enabling services in a move that has telecommunications companies around the world worried their profits could soon be under threat.

The product for Australians is essentially a relabelled version of telecommunications provider GigSky's data roaming service. It offers cheaper mobile broadband prices around the world compared with the service being sold by Telstra, Singtel-Optus and Vodafone Hutchison Australia.

For example, Australians travelling to the UK with an Apple SIM can buy 3 gigabytes of data for use during a 30-day period for $50.