The horse racing meeting at Ffos Las in South Wales will begin about two hours earlier on Wednesday because of the solar eclipse.
The UK and parts of Europe are set to experience the most significant solar eclipse in nearly three decades, which is set to begin shortly after 18:00 BST.
At other sporting events, including four Hundred cricket matches on Wednesday, floodlights will be turned on throughout matches.
It will be the most dramatic eclipse visible from the UK since 1999, and the first time a total eclipse can be seen from continental Europe since then too.
At Ffos Las, the first race was scheduled for 17:40 BST but that has now been rescheduled by the British Horseracing Authority to 15:35.
Officials at Kempton racecourse, which has races scheduled for 19:00 and 19:30, said there will be no disruption as all races were set to be under floodlights.
During the solar eclipse in August 1999, a League Cup football match between Torquay United and Portsmouth at Plainmoor stadium was postponed.
Devon and Cornwall Police forced the delay because an influx of tourists travelling to the English coast left local authorities under-staffed to safely manage stadium crowds.
It was played six days later.
