T-Mobile Czech Republic a.s. is the Czech subsidiary of T-Mobile International AG, which is owned by Deutsche Telekom. T-Mobile is part of one of the largest mobile telecommunications companies in the world. Deutsche Telekom's subsidiaries and affiliated companies serve over 120 million mobile customers worldwide. Besides its subsidiary in the Czech Republic, it operates mobile telecommunications companies in Great Britain, the United States, Germany, Austria, the Netherlands, Poland, and other countries. T-Mobile’s main business activities include operation of a public mobile communications network and provision of mobile network communications services to the public. T-Mobile’s network serves more than five million customers in the Czech Republic.