It operates GSM mobile telecommunications service in the Netherlands. It markets itself as being the cheapest option available, and goes to some lengths to give the appearance of being a no frills operator.
The company was formed in 1997 as a joint venture between British Telecommunications (BT) and Nederlandse Spoorwegen (Dutch Railways). In 2000, BT acquired the company. The group became part of the BT Wireless business and after its spin-off as mmO2, became known as O2 Netherlands. However in 2003, O2 sold the company to Greenfield Capital Partners. It then reverted to the Telfort name. In July 2005 Telfort was sold to telephone company KPN.
In October 2007, KPN, which had bought the Dutch operations of Tiscali some months earlier, rebranded Tiscali's Internet services as Telfort Internet. It has, since then, expanded its operations to include fixed phone lines and digital television (IPTV) subscriptions.