A capsule carrying three Chinese astronauts has docked with the Tiangong-1 space laboratory.
The procedure came two days after the crew blasted off from Inner Mongolia on a Long March 2F rocket.
The team plans to spend just under two weeks at the orbiting module, in what will be China's longest manned space mission yet.
The Xinhua news agency reported that the automated docking occurred at 13:11 Beijing time (05:11 GMT).
A good seal was confirmed seven minutes later.
After pressure checks, Xinhua said, the astronauts - Nie Haisheng, Zhang Xiaoguang and Wang Yaping - opened the hatch and entered Tiangong at 16:17 Beijing time.
This is China's fifth manned space mission, designated Shenzhou-10, and is scheduled to last 15 days in total.
Twelve days will be spent aboard Tiangong. One of the highlights will see Wang - China's second woman in space - present a video lecture to students on the ground in Chinese schools.
She will conduct at least one of these classes, demonstrating how objects move in the microgravity environment of space.
The published plan is for the crew to attempt a manual docking during their stay.
This will involve getting back inside their Shenzhou capsule, unhooking from Tiangong and then flying around the lab to re-attach with Nie at the controls.
This manoeuvre should occur on 20 June. The crew is expected to leave for good on 25/26 June. They will land in Inner Mongolia the same day.
Tiangong-1 has been in orbit for more than 600 days and has been visited by Shenzhou-8, Shenzhou-9 and now Shenzhou-10. But the lab does not have the resources aboard to support any more astronaut stays.
On completion of the Shenzhou-10 mission, Tiangong will be ditched in the atmosphere to burn up over the Pacific Ocean, although Chinese officials have not said yet precisely when this will happen.
A replacement lab, Tiangong-2, is likely to go up in the next couple of years. It will be a more ambitious module, paving the way for the big space station China hopes to launch at the end of the decade.