Indonesia, previously its largest source of tourists, was pushed to second place, followed by India, Malaysia and Australia, according to statistics released by the Singapore Tourism Board.
There were 8.24 million foreign arrivals in January-June, up 31% year-on-year and 88% of pre-Covid numbers.
In February Singapore announced a visa waiver for Chinese visitors, who have since been flocking to the city.
Thailand has received 17.5 million foreign tourists this year and Vietnam, 8.8 million. Chinese tourists were also the biggest group of arrivals to Thailand, and second to Vietnam after South Koreans.