London Buses route SL4 is a Transport for London contracted Superloop express bus route in London, England. Running between Grove Park station and Westferry Circus, it is operated by Go-Ahead London.
The service is one of three bus routes to run through the Silvertown Tunnel, alongside route 129 and the Silvertown Tunnel cycle shuttle.
History
The route was first proposed by Transport for London in November 2022 as part of the Silvertown Tunnel bus network. At the time of the consultation, the route was proposed to be numbered X239.
In March 2023, it was confirmed that the route would be introduced as planned and would also be included as part of the then proposed Superloop network of express bus routes. In October 2023, it was confirmed that the route would be introduced using route number SL4.
In 2023, the contract to operate the service was awarded to Blue Triangle, a subsidary of Go-Ahead London.
Route SL4 was introduced on 7 April 2025, the same day as the opening of the Silvertown Tunnel.
Current route
Route SL4 operates via these primary locations:
- Grove Park station
- Lee station
- Lee Green
- Blackheath station
- Blackheath Sun in the Sands
- Leamouth
- East India station
- Canary Wharf station
- Canary Wharf Westferry Circus
Operation
The route operates at a frequency of a bus every eight minutes on weekdays and every 15 minutes on weekends.
Like all bus services using the Silvertown Tunnel, the service is operated using zero emission battery electric buses. The service will be free to use for all passengers until at least April 2026.
References
External links
Media related to London Buses route SL4 at Wikimedia Commons
