The River Kwai Half Marathon is the oldest road race in Thailand.
The out and back course is one of the most scenic in Thailand. It takes runners up a gradual climb to the turn around point at 10.5 km. The declining return leg to the finish line will make for a fast second half of the race and most runners normally post a negative split at this race. There is also a 10K Run on offer which uses the same course with an earlier turn around point.
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Information about the event is available in : English