Nguyen Thi Tuyet Dung, Nguyen Thi Van and Huynh Nhu each scored a double in the game.
They put pressure on Indonesia's net right at the start, with forward Dung scoring from a freekick in the ninth minute.
The score changed quickly thanks to Nguyen Thi Van's header from Dung's pass in the 15th minute.
Van completed her double three minutes later when her freekick bounced off goalkeeper Norffince Boma to the net.
Not long after the second half started, star striker Huynh Nhu made her first goal in this year SEA Games with her right leg and raised the score to 4-0.
In the 61th minute, defender Vu Thi Thuy passed the ball to Nhu and the striker shook Indonesia's net again.
Dung finished the match with the sixth goal for Vietnam when no Indonesians were there to stop her in the 85th minute.
Coach Mai Duc Chung said it was an easy game for Vietnam and he had expected an even bigger win.
"They fulfilled their mission of winning and earning no cards or injuries. But they missed many chances," Chung said at the press conference after the game.
He said a bigger victory will guarantee Vietnam's top position of group B, whose remaining match between Indonesia and Thailand will be on Monday next week.
Vietnam had a 1-1 draw against Thailand on Tuesday.
Group A has Malaysia, Myanmar and hosts Philippines.
Vietnamese women took home the gold medal at the previous SEA Games, where Thailand won silver.