Japan has stopped its annual Antarctic whale hunt before the end of the season, saying "harassment" by US activists had made it impossible to continue.
The hunt had been halted temporarily last week, after the Sea Shepherd Conservation Society chased the Japanese fleet`s mother ship.
Now the fisheries minister says the fleet will return home.
Sea Shepherd said the decision was "great news".
"We will however stay with the Japanese ships until they return north and make sure that they`re out of the Southern Ocean whale sanctuary," Paul Watson, founder of the Sea Shepherd group, told the Agence France-Presse news agency.
Commercial whaling was banned in 1986 but Japan uses a regulation permitting hunting for scientific research.
Iceland and Norway have lodged official objections to the ban and continue to hunt commercially.
Japan had said it had suspended its hunt on 10 February. Normally the season continues until mid-March.
Announcing that whaling was being abandoned for this season, Japan`s Farm and Fisheries Minister Michihiko Kano said: "Even now the mothership is being chased, and it is difficult to ensure the safety of the crew members."
Activists` ships have been harrying the fleet for weeks in the icy seas of Antarctica.
The Sea Shepherd Conservation Society says one of its boats has been blocking the main ship`s stern loading ramp, preventing any harpooned whales from being loaded on to the ship.
Japan`s fleet involves 180 people on four ships, with the aim to kill up to 945 whales in Antarctic waters during the southern winter season.
Japan says it continues to hunt for scientific research, while not concealing the fact that much of the meat ends up on dinner plates, the BBC`s Roland Buerk in Tokyo reports.
Few Japanese eat whale regularly, but many object to what they see as unjustified foreign interference in a cultural tradition, our correspondent adds.
Anti-whaling nations, led by Australia and New Zealand, and environmental groups say the hunts are cruel and unnecessary. Australia is taking legal action in the International Court of Justice against Tokyo over whaling.