4G mobile coverage on the Tube has reached its halfway milestone, with TfL and infrastructure firm Boldyn Networks still targeting full roll-out across the Underground by the end of this year despite earlier delays.
The scheme aims to bring continuous 4G (and ready-for-5G) mobile connectivity to almost all London Underground stations and tunnels, allowing passengers to call, text and use data throughout their journeys.
It forms part of a wider push to modernise the Tube, improve passenger experience and generate extra commercial revenue for TfL through long-term infrastructure partnerships.
The main project had originally been due to complete by the end of 2024 but has slipped, largely because engineers have struggled to find suitable, safe locations inside stations to house radio and network equipment. Work also has to be done during tightly restricted “engineering hours” between about 1am and 4.30am, when no trains are running, which significantly limits how much can be installed each night and has slowed overall progress.
When can we expect 4G mobile coverage on the Tube?
With the project at the halfway stage, a growing number of lines and sections now offer live 4G coverage in stations and tunnels, giving many passengers their first experience of uninterrupted connectivity underground.
The remaining sections are due to be switched on in phases through 2026, with TfL and Boldyn prioritising complex central interchanges and older, more constrained stations that require more bespoke engineering work.
Once complete, most Tube users will be able to stay online for navigation, messaging, streaming and remote work for the duration of their journeys, rather than only at station entrances or on platforms.
The network is also expected to support better real-time travel information and operational communications, which could help manage disruption more effectively during busy periods or incidents.
TfL and Boldyn remain committed to completing the system-wide roll-out by the end of the year, while continuing to navigate the practical constraints of installing equipment in a 160‑year‑old underground network. As more sections go live, London is set to join a growing group of global cities whose metro systems offer near-seamless mobile connectivity.