The Isle of Man government has suspended its air bridge with Guernsey after the Channel island reported seven cases of coronavirus.
Guernsey's Chief Minister Peter Ferbrache confirmed the decision.
Those returning from the Isle of Man will not need to self-isolate, Mr Ferbrache added.
From 22 July people were able to travel freely between the Isle of Man and Guernsey without being subjected to any requirements to quarantine themselves.
Manx Chief Minister Howard Quayle confirmed the flights had been stopped "with immediate effect" and arrangements were being made to get people home to their respective islands.
Those returning to the Isle of Man would "likely" be required to self-isolate for 14 days, Mr Quayle said.
The decision had been taken "in order to protect our community" from the virus, he added.
Mr Ferbrache said of the move: "I don't think they've overreacted, I think we may well have taken the same decision if the boot had been on the other foot, but it is a suspension... they want it lifted as soon as possible."
"It will reopen as soon as they feel comfortable," he added.
All seven Covid-19 cases on Guernsey have been linked.
Guernsey States-owned airline Aurigny has been operating the flights.
It has announced the cancellation of its half-term services and said details about a repatriation service on Saturday for those who have already travelled would follow.