The British and Chinese navies have started their first joint maritime search and rescue exercises.
HMS Exeter arrived in China to a welcome from a military band
The move is part of a push by Beijing to boost military co-operation with other nations.
Each side will launch a helicopter to rescue victims of a mock shipping accident near the north-eastern port of Qingdau, the British Embassy said.
The drills follow similar exercises in recent months between China's navy and ships from Pakistan, India and France.
Britain is represented by the guided missile destroyer HMS Exeter and tanker RFA Grey Rover, the embassy said.
They are joined by guided missile destroyer Harbin and fuel tanker Hongze Lake of the People's Liberation Army Navy's North Sea Fleet.
David Snelson, chief of British maritime forces, said the drills were "the first step" in a gradual upgrading of cooperation between the militaries.
"We need time to better understand each other since we have differences in languages, communication methods, commanding means and so on," he said.
China has invited military attaches from 15 nations to observe the exercises on Sunday.
They will show "the new concept of China's military diplomacy against the backdrop of military reform with Chinese characteristics," China's official Xinhua News Agency said.