This is a self-navigated series of ultramarathons with a choice of 3 race distances. The 100 mile race begins in Blaxhall at 7.00am on the Saturday, 50 miles begins in Trimley at 3pm and the 50km begins in Shotley at 6am on the Sunday.

The 100 mile is a 100M UTMB index race. The 50 mile & 50km routes are 50km UTMB index races.

Cut-offs are generous, we want all of you reaching the iconic red buoy which denotes the official finish in Harwich.

2025 saw 100% of female entrants finish across all race distances.

We also organise recce runs of the route, including headtorch runs starting in November - follow our socials via the links at the bottom to keep up to date!

Click on the external Five Rivers Ultra website link for more details or enter via the button below

Our events are run under licence with The Trail Running Association under UK Athletics rules. As such there are age limits that govern the distances each age group is allowed to cover. For the purposes of The Five Rivers Ultra you must be 20 years or above to enter.