At Heidelberg X-TREM, participants carry a GPS tracker so friends and family can follow their progress live. The main event is a 100km Ultramarsch around Heidelberg, Germany, scheduled for September. It is positioned between a long-distance hike and an ultra-running challenge. Entries are divided into Hiker (walking only), Hike n' Run (walking with some jogging), and Runner (for ultra and trail runners).
The event also offers a 60km trail option on a loop starting from Heidelberg, passing through Dilsberg, Ritschweiler, and Schriesheim before returning to Heidelberg. This route includes 1,980 meters of elevation gain and has a 16-hour time limit. The field is limited to 500 tickets sold, making it smaller than many large city ultras. Only the Runner category is reported to the German Ultrarunners Association, and the DUV listing indicates the race is not eligible for ranking statistics.