Swimming at the 2017 SEA Games

The swimming competitions at the 2017 SEA Games in Kuala Lumpur took place at National Aquatic Centre in Bukit Jalil. It was one of four aquatic sports at the games, along with diving, water polo, and synchronised swimming. Meanwhile, marathon swimming was held at the Putrajaya Lake.

The 2017 Games featured competitions in forty events (20 events for men and 20 events for women).

Events
Similar to the program's format in 2015, swimming features a total of 40 events (20 each for men and women), including two 10 km open-water marathons. The following events will be contested (all pool events are long course, and distances are in metres unless stated):
 * Freestyle: 50, 100, 200, 400, 800 (women), and 1,500 (men);
 * Backstroke: 50,100 and 200;
 * Breaststroke: 50,100 and 200;
 * Butterfly: 50,100 and 200;
 * Individual medley: 200 and 400;
 * Relays: 4×100 free, 4×200 free; 4×100 medley
 * Marathon: 10 kilometres

Participating nations

 * (7)
 * (20)
 * (4)
 * (23)
 * (4)
 * (8)
 * (27)
 * (23)
 * (1)
 * (17)