During these trips, Chinese tourists spent 148 billion yuan ($21 billion), a 128.9% increase from a year earlier, and on a par with 2019 levels.
The figures from this year's May Day holiday - the first travel season since the pandemic without restrictions - are being monitored as a gauge of China's economic health.
Official data on Sunday showed activity in China's non-manufacturing sector grew in April, albeit at a slower pace than in March.
The travel boom during the May holiday "can be seen as a turning point of China's tourism sector", official Xinhua News Agency said on Wednesday.
The China Tourism Academy estimates about 4.55 billion domestic tourist trips will be made this year, up 73% from 2022, Xinhua reported.