Fiji's Supreme Court lifted a stay order which had prevented the U.S. from seizing the superyacht Amadea.
A US Justice Department's Taskforce has focused on seizing yachts and other luxury assets of Russian oligarchs in a bid to pressure Russian President Vladimir Putin over the war in Ukraine.
The 106m Amadea arrived in Fiji on 13 April after an 18-day voyage from Mexico.
It was seized by Fiji authorities after the country's High Court granted a US warrant last month that linked the yacht to sanctioned Russian oligarch Suleiman Kerimov.
The FBI has said the US$300 million luxury vessel had running costs of $25m to $30m per year, and the United States would pay to maintain the vessel after it was seized.
However, Fiji's government has been footing the bill while an appeal by the vessel's registered owner, Millemarin Investments, worked its way through the country's courts.
The Supreme Court ruled on Tuesday that public interest demands the yacht "sail out of Fiji waters", because having it berthed in Fiji was "costing the Fijian Government dearly," according to the judgment.
The vessel "sailed into Fiji waters without any permit and most probably to evade prosecution by the United States," it added.
Anthony Coley, a spokesperson for the U.S. Justice Department, posted on Twitter that the Amadea set sail for the United States on Tuesday "after having been seized as the proceeds of criminal evasion of US sanctions against Russian oligarch Suleyman Kerimov."
The United States alleges Kerimov beneficially owns the Amadea, although lawyers for the vessel have denied this and told the court it was owned by another Russian oligarch, Eduard Khudainatov, the former chief of Russian energy giant Rosneft, who has not been sanctioned.
Last month, another luxury yacht reportedly owned by Khudainatov worth some $700 million was impounded by police in Italy.
The FBI said in the seizure warrant the Amadea had tried to avoid being seized "almost immediately" after Russian troops entered Ukraine, turning off its automated tracking system on February 24.
The vessel's lawyer, Feizal Haniff, declined to comment on the judgement.
"The decision acknowledges Fiji's commitment to respecting international mutual assistance requests and Fiji's international obligations," Fiji's Director of Public Prosecutions, Christopher Pryde, said in a statement.
He said the court agreed "issues concerning money laundering and ownership" needed to be decided in the originating U.S. court.
Photo: Twitter/ Anthony Coley DOJ Caption: Russian superyacht Amadea sails out of Lautoka port on its way to the US.