The Tunnel Marathon - Portsmouth
Portsmouth, United Kingdom • 21 Nov 2026
The Tunnel Marathon
The Tunnel Marathon is a unique running event held entirely underground in the Ucap Bunker, located approximately two miles north of Portsmouth. This venue is situated 100 feet below the surface in a former underground headquarters once used by the Royal Navy. The facility is currently utilized for airsoft training and military exercises.
The event follows a lapped course through a series of underground tunnels. Participants should be aware that some sections of the tunnels are approximately 6 feet tall, which requires stooping for a distance of about 20 meters during each lap. The marathon is conducted under ARC running club rules, and the necessary permits and insurance are managed by the event organizers.
Participation is open to individuals aged 18 or older. Due to the subterranean environment, specific safety equipment is mandatory for all runners. Each participant must wear a cycle helmet and a headtorch for the duration of the event. Entry is restricted to 100 participants.
- Marathon
The location is accessible via the postcode PO17 6AR. The event maintains a strict policy regarding entries, with no refunds or transfers permitted for registered participants. Visit the organization's website for the most recent information.