Swimming at the 2015 Indian Ocean Island Games was held at Piscine Michel Debré, Saint-Denis, Réunion.
| 50 m freestyle | 23.10 | 23.30 | 24.30 NR | ||||
| 100 m freestyle | 50.50 | 52.20 | 53.30 | ||||
| 200 m freestyle | 1:51.50 | 1:55.70 | 1:56.90 | ||||
| 400 m freestyle | 3:54.97 | 4:15.29 | 4:18.07 | ||||
| 1500 m freestyle | 15:30.10 | 17:16.20 | 17:20.90 | ||||
| 50 m backstroke | 26.90 | 28.60 | 29.40 | ||||
| 100 m backstroke | 58.40 | 1:01.34 | 1:02.32 | ||||
| 200 m backstroke | 2:16.20 | 2:18.40 | 2:18.60 | ||||
| 50 m breaststroke | 29.26 | 29.55 | 30.16 | ||||
| 100 m breaststroke | 1:04.00 | 1:06.10 | 1:07.00 | ||||
| 200 m breaststroke | 2:19.50 | 2:22.00 | 2:31.60 | ||||
| 50 m butterfly | 24.60 | 25.40 | 25.50 | ||||
| 100 m butterfly | 55.57 | 56.11 | 57.80 | ||||
| 200 m butterfly | 2:07.20 | 2:08.70 | 2:20.80 | ||||
| 200 m individual medley | 2:07.10 | 2:17.20 | 2:17.80 | ||||
| 400 m individual medley | 4:38.40 | 4:50.60 | 4:54.20 | ||||
| 4 × 100 m freestyle relay | Vincent Bradley Darren Chan Chin Wah Yohan Lim Mathieu Gilles Marquet | 3:28.23 | Mathieu Bachmann Nathan Mandere Dimitri Faubourg Benoît Debast | 3:29.10 | Steeven Mangroo Adrian Nanty Dean Hoffman Adam Viktora | 3:40.03 | |
| 4 × 200 m freestyle relay | 7:41.70 | 8:02.60 | 8:17.60 | ||||
| 4 × 100 m medley relay | 3:52.41 | 4:02.76 | 4:11.43 | ||||
| 50 m freestyle H | 27.9 | 33.9 | - | - | |||
| 50 m freestyle H | 33.0 | 55.5 | - | - | |||
| 50 m freestyle adapted | 35.8 | 36.1 | - | - |
| 50 m freestyle | 26.60 | 26.68 | 26.72 | ||||
| 100 m freestyle | 56.30 | 58.30 | 58.80 | ||||
| 200 m freestyle | 2:04.30 | 2:08.10 | 2:09.10 | ||||
| 400 m freestyle | 4:19.03 | 4:26.32 | 4:46.62 | ||||
| 800 m freestyle | 9:21.00 | 9:25.60 | 9:55.40 | ||||
| 50 m backstroke | 29.50 | 31.10 | 31.60 | ||||
| 100 m backstroke | 1:03.52 | 1:06.27 | 1:06.40 | ||||
| 200 m backstroke | 2:22.80 | 2:26.80 | 2:27.10 | ||||
| 50 m breaststroke | 33.49 | 34.15 | 34.79 | ||||
| 100 m breaststroke | 1:13.20 | 1:15.40 | 1:20.00 | ||||
| 200 m breaststroke | 2:37.70 | 2:47.70 | 3:05.10 | ||||
| 50 m butterfly | 28.04 | 28.50 | - | - | |||
| 100 m butterfly | 1:01.99 | 1:02.67 | 1:03.86 | ||||
| 200 m butterfly | 2:19.90 | 2:27.20 | 2:28.60 | ||||
| 200 m individual medley | 2:24.20 | 2:24.70 | 2:30.20 | ||||
| 400 m individual medley | 5:05.6 | 5:15.1 | 5:46.8 | ||||
| 4 × 100 m freestyle relay | Aïnoa Boucher Mathilde Hoareau Emma Morel Alizée Morel | 3:56.30 | Heather Ann Arseth Ann Her Elodie Poo Cheong Olivia Chan Chee de Maroussem | 3:58.80 | Alexus Laird Leyla Monti Anisha Payet Felicity Elizabeth Passon | 4:12.20 | |
| 4 × 200 m freestyle relay | 8:39.33 | 8:54.10 | 8:54.13 | ||||
| 4 × 100 m medley relay | 4:21.52 | 4:31.44 | 4:47.84 | ||||
| 50 m freestyle D | 38.8 | 47.0 | - | - | |||
| 50 m freestyle D | 1:01.8 | 1:22.9 | - | - | |||
| 50 m freestyle adapted | 42.9 | 55.6 | - | - |