The Girls' 420 (U19) is a sailing event on the Sailing at the SEA Games programme at the National Sailing Centre.

All times are Singapore Standard Time (UTC+08:00) [1] [2] If sailors are disqualified or do not complete the race, 7 points are assigned for that race with 6 boats, 6 points for race with 5 boats, and 5 points for race with 4 boats Scoring abbreviations are defined as follows: