Swimming at the 2011 SEA Games was held in Palembang, Indonesia from 12 to 17 November 2011.

The competition featured 38 events (19 male, 19 female) swum in a long course (50m) pool.

This was the first games to be held since non-textile swimsuits were banned in January 2010.

Women's water polo made its SEA Games debut in the 26th edition of the sporting event.

Indonesia, Malaysia, and Singapore were the only teams to compete after the Philippines and Thailand withdrew.