HAAS Maraton Váltó is a trail-running marathon relay in Tata, Hungary, based at Tópart sétány 10 by the lake. It starts at 10:00 in the morning and runs into the afternoon, with registration, changing, and bib pickup open from 8:00 at the SPRINT clubhouse. The race is marked as rough, with a medium physical load, so it sounds more like a steady off-road effort than a flat road time trial.
The course is built around 7 km laps of the lake. Solo runners can do one lap, three laps for 21 km, or six laps for the full 42 km, while relay teams cover the marathon as six 7 km legs. Teams can have 2 to 6 runners, and the order is flexible enough to change on site. Someone without a team can still join for a single lap, which makes the event work for both relay groups and individuals who just want the lake loop.