The typhoon hit Vietnam after killing at least two people and injuring 92 others on southern China’s Hainan island.
State broadcaster CCTV said Yagi brought winds of more than 230kmh, uprooting trees and prompting the evacuation of around 460,000 people.
Hainan’s main airport in Haikou was closed until 3pm on Saturday, according to state broadcaster CCTV.
Authorities in the neighbouring province of Guangdong said on Friday that they had evacuated more than 574,000 residents to safety.
Yagi killed at least 13 people in the Philippines earlier this week when it was still classified as a tropical storm, before strengthening into a super typhoon over the next few days.
Typhoons in the region are now forming closer to the coast, intensifying more rapidly, and staying over land for longer due to climate change, according to a study published in July.