Gremlins Marathons & Half Marathons 2026

The Gremlins Marathons & Half Marathons is a three-day race series held in December at Caldecotte Lake in Milton Keynes. Marathon and half marathon races are offered on each of the three days. Participants may enter a single event or multiple races over the weekend, which suits those aiming for several finishes under the 100 Marathon Club guidelines. The course consists of laps around Caldecotte Lake: 7.5 laps are needed for the marathon and 3.5 laps for the half marathon. Registration provides on-site route details. Each race has official support, including a starter, timekeeper, and referee. Aid stations with water and toilets are positioned on every lap. The marathon has a seven-hour time limit, and the half marathon has a four-hour limit. All finishers are awarded a custom medal.