The Tunnel Marathon - Portsmouth

The Tunnel Marathon - Portsmouth

The Tunnel Marathon is scheduled for 21 November 2026 at UCAP BUNKER, a venue about 2 miles north of Portsmouth with postcode PO17 6AR. The location is situated approximately 100 ft underground in a former U.G.H.Q used by the Royal Navy to plot allied movements during the Normandy invasion.

The event is presented as a fully underground marathon. The route uses several tunnels, including sections with a 6 ft clearance that require some stooping for taller runners; these low sections are typically around 20 m long and occur repeatedly because the course is lapped. Headtorch and cycle helmet are mandatory equipment.

The event is organised under ARC Running Club rules and permit and insurance details are displayed at the start. Entries opened on 6 March 2026 and closed on 14 November 2026. The organisers reported 100 participants and state the event is now full. Minimum age for entry is 18 years. Entry fees were listed as £60 for affiliated runners and £62 for unaffiliated runners. The organiser specifies that there are no refunds or transfers for this race.

Permit, insurance and the event disclaimer are available to participants at the event. Visit the organization's website for the most recent information.