Indonesia had planned to send 556 athletes to the biennial multi-sport event for the 11 nation bloc, but Youth and Sports Minister Imam Nahrawi said a number of factors, including quotas from organisers, the removal of some sports, and focusing on genuine medal hopes, had resulted in the cut.
Indonesia is targeting 70 gold medals at the event, with badminton expected to be one of their strongest suits.
Indonesia is the most successful nation at the Southeast Asian Games having topped the medal table on 10 occasions, including nine times in an 11-event stretch until 1997.
The country finished a disappointing fourth in Myanmar two years ago and Imam stated that the aim was to finish in the top two in Singapore.