The 2021 ISL regular season has had some impressive swims, including 7 new ISL Records and 1 World Record.
First, in Match 2, Coleman Stewart produced a 48.33 in the 100 backstroke to shave 0.25 from Kliment Kolesnikov‘s 2020 World Record, set in the 2020 ISL Grand Final. Later, in Match 3, Sarah Sjostrom put up a 23.17 in the 50 freestyle, taking 0.19 from the former ISL Record and coming in as the 5th-fastest performance all-time. Kelsi Dahlia posted a 55.22 in the 100 butterfly in Match 4, shaving 0.10 from the former mark set by Beryl Gastaldello in 2020.
The mixed 4 x 100 medley relay is a new event in season 3, therefor the first time it was swum in Match 1 the winning team, the Toronto Titans, set the record with a 3:35.89. The Cali Condors took 0.02 off this mark in Match 2, and then in Match 4 the LA Current lowered the mark to 3:33.81, shaving a full two seconds from the week-old record. Then, in Match 8, Energy Standard lowered the record to a 3:31.96, which still stands after Match 10. FINA does not recognize the mixed 4 x 100 medley relay in short course competition and therefor has no records listed for the event. However, given Energy Standard’s dominant performance the the fact that the mixed 4 x 100 medley relay is not contested in other major international swim meets we conclude Energy Standard’s ISL Record is also a ‘World Best.’ The ISL Record in the mixed 4 x 100 medley relay has been broken 4 times in season 3, though since it is a new event that is not necessarily surprising.
There have been other notable swims in season 3 that did not break an ISL Record. For example, Nicholas Santos produced a 21.83 in the 50 butterfly in Match 10, the 6th-fastest performance all-time, but not as fast as Santos’ own ISL Record which stands at 21.78 set in season 2. Ilya Shymanovich swam a 25.41 in the 50 breaststroke in Match 3, though this falls 0.12 short of Emre Sakci‘s 2020 ISL Record. Evgenia Chikunova lowered her own World Junior Record in the 200 breaststroke with a 2:17.57 in Match 9, however this time is not quite as quick as Lilly King went in Match 6 and though impressive is not the fastest time this season.
Caeleb Dressel has the most top times in the regular season with 4 while Ilya Shymanovich and Daiya Seto each have 3 top times this season. The top performers on the women’s side are more diverse and only three women, Lilly King, Beata Nelson, and Kelsi Dahlia, all of the Cali Condors, have registered multiple league-leading swims. In total, the Cali Condors own 13 top times in season 3: 6 on the men’s side and 7 on the women’s side. Energy Standard, meanwhile, only owns 8 of the best performances this season, with 4 on the men’s side, 3 on the women’s side, as well as the mixed medley relay. The London Roar has achieved 5 top times (3 men’s and 2 women’s), while Iron has registered 2 top times, both in the 50 butterfly. The DC Trident has also achieved 2 top times while the Toronto Titans, the Aqua Centurions, the LA Current, and the New York Breakers all have just 1 top time. The Tokyo Frog Kings have 3 of the top times this season, all coming from Daiya Seto.
Fastest Performances of the 2021 ISL Regular Season
| Match | Team | Swimmer | Time | Event | Time | Swimmer | Team | Match |
| Match 3 | Energy Standard | Sarah Sjostrom | 23.17* | 50 Freestyle | 20.67 | Caeleb Dressel | Cali Condors | Match 4 |
| Match 8 | London Roar | Emma McKeon | 51.05 | 100 Freestyle | 45.47 | Caeleb Dressel | Cali Condors | Match 4 |
| Match 9 | Energy Standard | Siobhan Haughey | 1:52.25 | 200 Freestyle | 1:41.72 | Duncan Scott | London Roar | Match 9 |
| Match 5 | Toronto Titans | Summer McIntosh | 3:58.78 | 400 Freestyle | 3:39.20 | Brendon Smith | NY Breakers | Match 10 |
| Match 5 | DC Trident | Ali DeLoof | 25.98 | 50 Backstroke | 22.60 | Guilherme Guido | London Roar | Match 3/Match 6 |
| Match 8 | LA Current | Ingrid Wilm | 55.61 | 100 Backstroke | 48.33** | Coleman Stewart | Cali Condors | Match 2 |
| Match 7 | Cali Condors | Beata Nelson | 2:00.55 | 200 Backstroke | 1:49.61 | Evgeny Rylov | Energy Standard | Match 1 |
| Match 10 | Aqua Centurions | Arianna Castiglioni | 29.09 | 50 Breaststroke | 25.41 | Ilya Shymanovich | Energy Standard | Match 3 |
| Match 7 | Cali Condors | Lilly King | 1:03.53 | 100 Breaststroke | 55.63 | Ilya Shymanovich | Energy Standard | Match 8 |
| Match 6 | Cali Condors | Lilly King | 2:16.83 | 200 Breaststroke | 2:02.10 | Ilya Shymanovich | Energy Standard | Match 8 |
| Match 5 | Iron | Ranomi Kromowidjojo | 24.81 | 50 Butterfly | 21.83 | Nicholas Santos | Iron | Match 10 |
| Match 4 | Cali Condors | Kelsi Dahlia | 55.22* | 100 Butterfly | 48.53 | Caeleb Dressel | Cali Condors | Match 4 |
| Match 4 | Cali Condors | Kelsi Dahlia | 2:03.95 | 200 Butterfly | 1:49.41 | Daiya Seto | Tokyo Frog Kings | Match 8 |
| Match 7 | Cali Condors | Beata Nelson | 57.90 | 100 IM | 50.68 | Caeleb Dressel | Cali Condors | Match 4 |
| Match 9 | London Roar | Sydney Pickrem | 2:04.59 | 200 IM | 1:51.12 | Daiya Seto | Tokyo Frog Kings | Match 6 |
| Match 4 | DC Trident | Bailey Andison | 4:26.31 | 400 IM | 3:58.65 | Daiya Seto | Tokyo Frog Kings | Match 10 |
| Match 8 | Energy Standard | Haughey, Heemskerk, Teijonsalo, Sjostrom |
3:27.65 | 4 x 100 Free Relay | 3:05.05 | Chalmers, Nakamura, Mildred, Carter | London Roar | Match 6 |
| Match 6 | Cali Condors | Nelson, King, Dahlia, Brown |
3:47.70 | 4 x 100 Medley Relay | 3:20.68 | Stewart, Fink, Dressel, Ress |
Cali Condors | Match 4 |
Mixed 4 x 100 Medley Relay
| 4 x 100 Mixed Medley | 3:31.96* | Rylov, Shymanovich, Shkurdai, Sjostrom |
Energy Standard | Match 8 |
*ISL Record
**World Record
