O2’s free London Underground Wi-Fi service launched today (Thursday 11th), and is now available to all O2 customers.

According to techweekeurope.co.uk, the service was originally supposed to launch back in June but it ran into technical problems, so it was pushed back to July 22nd. However, after successful testing, the service has rolled out today, 11 days early.

O2 customers can access the free Wi-Fi in 121 tube stations and they can connect from the ticket office to right down on the platform. The free Wi-Fi however, cannot be accessed on the trains themselves, reports thenextweb.com

The wireless service is provided by Virgin Media via their fibre optic network. O2 is the third major mobile provider to sign up to the service, following EE and Vodafone, leaving only Three to join the party.

Both contract and PAYG (pay-as-you-go) customers can access the Wi-Fi by simply signing up to O2 Wi-Fi. Once they’ve signed in to the network once, their device will automatically connect to the network every time it detects it. Customers who haven’t already signed up for O2 Wi-Fi can do so by connecting to any O2 hotspot. Alternatively, you can download the app from the App Store if you’re an Apple user, or the Google Play store if you’re an Android user.