The SIM card is compatible with unlocked GSM phones and the main phone number, once the SIM card is inserted, is based in the EU. Customers can add phone numbers in the U.S. and many other countries for an additional cost.
OneSimCard has a special Mobile app for both Android and iPhones, OneSim VOIP, which makes calls at very low rates when connected to a Wi-Fi network. Currently, OneSim VoIP is available only for phones which use Android OS 2.0 and higher or Apple iOS 4.0 or higher (iPhone, iPad, iPod Touch).
There are no contracts or monthly fees to use OneSimCard service and additional features are available for businesses to manage any number of traveling employees via a flexible web-based account management system.
The company launched its OneSimCard Connect app on Android in September 2013, allowing users to make calls to a OneSimCard-powered phone at no cost from anywhere in the world with only a data connection required, as long as the OneSimCard customer receiving the call has the feature for this service activated.