London Underground mobile connectivity map

Mobile connectivity on the Tube

Mobile connectivity on the London Underground is provided by a combination of leaky feeders in tunnels and DAS units in stations. The programme is operated by Boldyn Networks (previously known as BAI Communications) as part of a 20-year concession awarded by Transport for London.

The programme entails full mobile connectivity throughout the London Underground by the end of 2024, including 5G connectivity at select stations. As of yet, the rollout is not complete, hence a map of deployments and other information is useful for those interested in tracking the rollout over time.

Using the map

Sections of the network that have mobile connectivity within stations and tunnels are highlighted in green. Sections highlighted in orange are planned to open soon.

If you'd prefer, you can hide all sections of the network that don't have connectivity, or show and hide particular lines.

You can also click or tap stations and sections of line on the map to reveal what services (2G/3G/4G/5G) are available in that area for each mobile operator.

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Deployment info

UK networks are deploying pre-determined and standardised coverage at each station and tunnel section across the network. Low footfall stations receive the standard 2G, 3G and 4G, while higher footfall stations get 5G coverage on top of this. Thankfully, this makes demonstrating the available coverage across the network simpler for us.

The Jubilee Line Extension coverage which launched in March 2020 has differences compared to the widespread rollout that began in December 2020. Namely that overall capacity is lower due to less spectrum being active, and that some networks focused on legacy technologies in order to consistently provide voice services.

Jubilee Line Extension

As the first section of the sub-surface London Underground to receive mobile connectivity, the JLE has a more limited deployment of spectrum and radio technologies.

Three — Deployment in Jubilee Line Extension stations

2G	3G	4G	5G
G18	╳	B1B3B7B7	╳
╳	╳	B1B3	╳
╳	U09U21U21	B1B20B40B40	╳
╳	U09U21	B1B7B8B20	╳

Deployment in Jubilee Line Extension tunnels

2G	3G	4G	5G
G18	╳	B1B3	╳
╳	╳	B1B3	╳
╳	U09	B20	╳
╳	U09	B20B8	╳

Wider rollout

The wider mobile coverage rollout is generally unified across all tunnel segments, however stations have both 5G and non-5G configurations present.

The Elizabeth line will not have 5G coverage at any station or tunnel segment due to potential interference issues with the signalling equipment on the line. It is unclear whether this means any 5G, or only mid-band 5G, such as n78. There would be no reason to ban 5G connectivity as a whole as low-band (sub 3 GHz) frequencies are already used for 4G LTE coverage on this line.

The major point to note is the lack of 3G at newly deployed stations for all networks except Vodafone. It is likely Vodafone's 3G will be switched off by the end of 2023 as part of their nationwide 3G switch-off programme.

2G	3G	4G	5G
G18	╳	B1B3B3B7B7	n78n78
╳	╳	B1B3	n78n78
G18	╳	B1B20B40B40	n78
G09	U21	B1B3B7	n78n78

2G	3G	4G	5G
G18	╳	B1B3B3B7B7	╳
╳	╳	B1B3	╳
G18	╳	B1B20B40B40	╳
G09	U21	B1B3B7	╳

Each tunnel segment is fed by the station at either end of the tunnel, with a split in the leaky feeders mid-way through the tunnel. It has been noted during testing that some networks have not configured devices to hand over between the two leaky feeder sections, which can lead to a brief loss of connectivity mid-way through a tunnel.

Illustration of the London Underground leaky feeder configuration.

Three does not have 5G service inside tunnels yet, but it is likely that they will deploy n28 in the future, similar to O2 and EE, as they have spectrum holdings within this band. Elizabeth line tunnel coverage is not live yet, but it is possible they will not contain 5G coverage shown below that is present on other TfL tunnels.

2G	3G	4G	5G
G18	╳	B1B3B3B20	n28
╳	╳	B1B3	╳
G18	U09	B1B8B20	n28
G09	U21	B1B20B3B8	n8

Heathrow tunnels

The tunnels between the Great Western Mainline and Heathrow Airport are privately owned by Heathrow Airport Holdings rather than being part of Network Rail's infrastructure. They were also some of the first railway tunnels to gain a specialist mobile phone coverage solution.

Stretching back as far as 2009 (or earlier), the Heathrow tunnels have had a mobile coverage solution of some form, starting with 2G only for Orange, and moving up to today's 4G solution covering all four UK networks.