EE and Vodafone customers will be able to make use of Virgin Media's London Underground Wi-Fi network for free from early 2013.
The two mobile operators have signed up as wholesale partners for Virgin Media's Wi-Fi service, meaning that customers on those networks will continue to get free access to the network when Virgin Media starts charging the public for it next year.
"Wi-Fi on London Underground has been an incredible success with over 700,000 people already online and a remarkable million sessions every day. We're rolling out the service to reach even more stations throughout London, from Camden Town to Clapham Common and, thanks to our partnership with EE and Vodafone, the majority of Tube users can stay connected for no extra cost," Jon James, executive director of broadband at Virgin Media, said in a statement.
Customers on the Orange and T-Mobile networks will also get free access to the service. EE is the amalgamation of the two operators' brands in the UK.
Ahead of the official announcement of the deal, some confusion was caused by EE's official Twitter account informing followers of the deal, but then deleting the tweet and retracting the statement. The message on Twitter was "posted in error", a spokeswoman said.
Virgin Media, which runs the Wi-Fi service on the London Underground, said in July that it was looking for wholesale partners to work with once it began charging for access. Until now it has been free to access for everyone, and will remain so until the beginning of 2013.
In addition to striking wholesale deals with EE and Vodafone, Virgin Media also said it was looking to bring another 48 stations online by "early next year", 20 of which are planned to go live before the end of next month.
The network is currently available at 72 stations; if it succeeds in switching on an additional 20 before the end of 2012, it will still be 28 stations behind its target of 120 switched on before Christmas.