The spaceship docked with the ISS at 16:55 Moscow time (1255 GMT), Mission Control spokesman Valery Lyndin said.
The spaceship brought to the station the crew of the 17th main expedition, Russian cosmonauts Sergei Volkov and Oleg Kononenko, who will work in orbit for over six months.
Also on board is the first South Korean woman cosmonaut, Yi So-yoen. She will carry out a series of scientific experiments in orbit before returning to earth together with Russian cosmonaut Yuri Malenchenko and U.S. astronaut Peggy Whitson, who have been working in orbit since last October.
Soyuz TMA-12 blasted off from the Baikonur cosmodrome in Kazakhstan on Tuesday. There have been three spaceship dockings to the ISS so far this year.
A Russian Soyuz TMA-12 spacecraft carrying the International Space Station (ISS) crew of South Korean astronaut Yi So-yeon and Russian cosmonauts Sergey Volkov and Oleg Kononenko, blasts off from the launching pad at Baikonur cosmodrome April 8, 2008.
A Russian Soyuz TMA-12 spacecraft carrying the International Space Station (ISS) crew of South Korean astronaut Yi So-yeon and Russian cosmonauts Sergey Volkov and Oleg Kononenko, blasts off from the launching pad at Baikonur cosmodrome April 8, 2008.