Winter Enigma Marathons
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Mystery Box Marathon & Half Marathon
The Mystery Box Marathon and Mystery Box Half Marathon take place on 12 November 2026 at the Premier Inn, Lakeside Grove, Bletcham Way, Caldecotte, Milton Keynes MK7 8HP. Both races use a clockwise lakeside loop around Caldecotte.
- Mystery Box Marathon: 7.5 scenic laps of Caldecotte Lake (clockwise)
- Mystery Box Half Marathon: 3.5 scenic laps of Caldecotte Lake (clockwise)
Route descriptions are provided at the event location. Mandatory race briefings take place ten minutes before each race. The event is held in accordance with 100 Marathon Club rules.
There are hard time limits: marathon finishers over 7:00 hours will be recorded as DNF, and the half marathon has a 4:00 hour limit. Support on the course includes a starter, timekeeper and race referee, plus water and toilet facilities every lap. A large pub car park is available near the venue.
All finishers each day receive a bespoke finisher medal. Participants are expected to wear suitable clothing and footwear. Entry fees are £39.99 for the marathon and £34.99 for the half marathon.
There are no refunds. Entries may be deferred up to seven days before the event and transferred to another Enigma event that is open to entries; deferred entries must be used within 18 months. Visit the organization's website for the most recent information.
