The reservists arrived in Crimea by ship on May 27, with plans to repair a local training base.
But their presence provoked protests by communists and pro-Russian parties, who said NATO was trying to gain a foothold in Ukraine.
The Defense Ministry in Kyiv said on June 11 that the reservists were leaving because their contract had ended. Associated Press reports, however, that no repair work was done at the base.
Ukraine's military cooperation with the West suffered an apparent setback when, on June 8, Ukraine and Britain postponed planned joint military exercises less than a week before they were due to start. Whether the exercises eventually take place will depend on parliament.
It will also be parliament that decides whether multinational military exercises, held annually under the name Sea Breeze, can go ahead, the head of the National Security and Defense Council, Volodymyr Horbulin, said on June 11.
President Viktor Yushchenko has invited 12 nations to join.