Marathon later recognized by the race organizers as the women's winner for that year, as well as 1967 and 1968. The length of an Olympic marathon was not precisely fixed at first, but the marathon races in the first few Olympic Games were about , roughly the distance from Marathon to Athens by the longer, flatter route. The exact length depended on the route established for each venue. The International Olympic Committee agreed in 1907 that the distance for the 1908 London Olympic marathon would be about 25 miles or 40 kilometres. The organisers decided on a course of 26 miles
Bangkok Marathon course passes many historical landmarks of cultural and ethnic importance. The marathon starts and finishes in front of The Royal Grand Palace at Sanam Chai Road. The race course is sanctioned by The Association of International Marathons and Distance Races (AIMS) and the Amateur Athletic Association of Thailand (IAAF Rules). In 2013, the course of the half marathon was changed at the last minute because of concurrent Bangkok street protests which reduced the distance of the half marathon from 21.1 km (13.1 miles) to 19.7 km (12.2 miles). In 2015, the half marathon was accidentally extended from 21.1 km (13.1