The opening ceremony started at 8:45 p.m. along the Han River.
The festival was last held in 2019 before Covid threw a spanner in the works.
This year's event has attracted pyrotechnic teams from eight countries, Australia, Canada, France, Italy, Poland, and the U.K. being the others.
Spectators watch from temporary stands built along the Han River. The number of people is limited to 5,000.
Tickets for the festival cost VND800,000-3 million (US$34-128).
Hundreds of tourists also admire the fireworks from boats on the Han River.
The city allows vessels in the river during the shows as long as they keep a safe distance from the fireworks.
The Finnish team set off fireworks to rock music followed by emotional songs and ending with joyful melodies calling for unity.
Canada and France will go next on June 10, Italy and Australia on June 17 and Poland and the U.K. on June 24.
The finals between the top two teams will be on July 8.