| 22 May 2021 |
Jemez Mountain (15 Miler|50 Miler|50K) |
Los Alamos, New Mexico, United States |
| 22 May 2021 |
Pen Llyn Ultra (100 Miles|50 Miles|75 Miles) |
Y Ffor, Wales, United Kingdom |
| 22 May 2021 |
Silver Moon Race (100-Miles|24-Hours|12-Hours|6-Hours) |
Reedley, California, United States |
| 22 May 2021 |
North Downs Way 50 (50 Miles) |
Waverley, England, United Kingdom |
| 22 May 2021 |
Silver Moon Race (100 Miles) |
Fresno County, California, United States |
| 22-29 May 2021 |
Bishop High Sierra Ultras (55K|50 Miler|100K) |
Bishop, California, United States |
| 23 May 2021 |
Hootenanny 50k (50k & Relay) |
Lolo, Montana, United States |
| 28 May 2021 |
Ancient Trails: Run the Ridgeway (Ancient Trails: Run the Ridgeway) |
Avebury, England, United Kingdom |
| 29 May 2021 |
Nanny Goat 100 (100 Miler) |
Riverside, California, United States |
| 29 May 2021 |
Survival of the Fittest 18k (18k) |
Squamish, British Columbia, Canada |
| 29 May 2021 |
Chester Ultra 100 (100 Miles) |
Waverton, England, United Kingdom |
| 29 May 2021 |
Pigtails Challenge (100 Miler) |
King County, Washington, United States |
| 29 May 2021 |
Grand Union Canal (145 Miles) |
Birmingham, England, United Kingdom |
| 29-31 May 2021 |
Stumptown Trail Runs (50K|1/2 Marathon) |
Portland, Oregon, United States |
| 29 May 2021 |
Survival of the Fittest 35k (35k) |
Squamish, British Columbia, Canada |
| 30 May 2021 |
Mountains 2 Beach (Marathon|Half-Marathon) |
Ojai, California, United States |
| 04 Jun 2021 |
Scout Mountain Trail Ultras (100 Miler) |
Pocatello, Idaho, United States |
| 4-6 Jun 2021 |
Ultra-Trail Snowdonia (50 Miles|100 Miles|30 Miles) |
Fachwen, Wales, United Kingdom |
| 04 Jun 2021 |
San Diego 100 (100 Miler) |
Lake Cuyamaca, California, United States |
| 05 Jun 2021 |
Old Dominion 100 Mile (100 Miler) |
Fort Valley, Virginia, United States |