Three subscribers are to gain free access to Virgin Media's Wi-Fi network on the London Underground.
At present, only Virgin Media, EE, Vodafone and O2 customers can use wireless services on the Tube for free.
But Danny Dixon, Director of Customer Strategy at Three, told TechRadar that his company has agreed a deal with the network operator to offer free access to its customers.
Three subscribers will be able to get online at 137 London Underground stations from the end of July.
Wi-Fi coverage is available in ticket halls and corridors and also on platforms - meaning passengers can access the web while they wait for their train.
Virgin Media installed the Wi-Fi network in time for the London 2012 Olympic Games.
Consumers who do not qualify for free access can still get online by purchasing a one-day pass for £2, a one-week pass for £5 or a one-month pass for £15.