The 11th Crew Dragon spacecraft of Space Exploration Technologies Corp., or SpaceX, carrying Yui and three foreign colleagues, was launched by a Falcon 9 rocket from NASA's Kennedy Space Centre in Florida on Friday local time.
The Crew-11 spacecraft was separated from the rocket 10 minutes after the launch and docked with the ISS in the small hours of Saturday. The launch was postponed for one day due to bad weather.
Onishi, 49, now in command of the ISS, greeted Yui with a high five after the connecting hatch opened about 80 minutes after the docking. They hugged and celebrated their reunion.
At a ceremony held afterwards, Onishi welcomed the four astronauts. Yui expressed his gratitude in English.
For Yui, this is the second space flight and the first since 2015. He is expected to stay on the ISS for about half a year.
During the period, he will conduct various experiments in the Japanese module Kibo. He may see the first unit of Japan's new cargo transporter HTV-X, a successor to Kounotori, arrive at the ISS.
Onishi is slated to return to Earth aboard the Crew-10 on Tuesday or later.
[Copyright The Jiji Press, Ltd.]