Brits on mobile phone contracts with Three will finally be able to access free Wi-Fi on the London Underground.

Three is the final ‘big four’ telecom provider to offer the service, which has been available to O2, Vodafone and EE customers since 2012. Danny Dixon, Three’s director of customer strategy, told techradar.com that customers will be able to get online for free by as early as the end of July.

Some 137 Underground stations will be covered by the network, as should all ticket halls, platforms and corridors. However, the Wi-Fi network can’t yet be accessed on trains when they’re in motion, reports stuff.tv.

Virgin Media provides the Wi-Fi service, for which the infrastructure was implemented just before the London Olympics in 2012. The service was free and open to all for quite some time, until a paywall was introduced in early 2013, meaning those who weren’t on Virgin, Vodafone, O2 or EE could only access the Wi-Fi if they paid for the privilege.

O2 finally announced it would be joining the party in April 2013, but the service rollout suffered delays and users weren’t actually able to log on until July that year. Now, more than one year on, Three has announced its involvement as well, so that its users would be able to circumvent the paywall and get online for free.