Marine Atlantic says it will attempt a ferry crossing between Nova Scotia and southern Newfoundland on Wednesday night.
The Joseph and Clara Smallwood MV has already left the dock at Port aux Basques, N.L., said Tara Laing, a spokeswoman for the Crown corporation.
The sailing is expected to take nine hours — three hours longer than normal.
Marine Atlantic had begun re-booking passengers stranded on either side of the Cabot Strait for crossings planned to start at 3 p.m. local time on Wednesday.
Three ferries were docked Monday night for what was expected to be 72 hours. Environment Canada then softened its forecasts for the Cabot Strait, as a fierce early-winter storm passed through Atlantic Canada.
Meteorologists said waves that had been as high as nine metres would drop to between six and eight metres on Wednesday afternoon and to as low as five metres by Wednesday night.
Before Wednesday's decision, Marine Atlantic said it would be difficult to transport a backlog of 800 reservations as well as what it called a "significant amount of commercial traffic" before Christmas Day.
Canada Post has already warned customers that Newfoundland-bound mail and packages in three large trucks will not make it to destinations by Christmas.
Paul White, who has been stranded in North Sydney while he waits for a ferry to Newfoundland, said he is trying to be patient.
"I wouldn't want to be out on the rough seas, so I guess I'm happy to be here," said White, a Cambridge, Ont., resident headed to his family home in Bell Island, just west of St. John's.
"But I'd be happier if I was on the other side. I'll have to wait and see."
On the other side of the Cabot Strait, passengers waiting to reach the mainland have also been biding their time.
Carol Mulrooney, who told CBC News earlier this week that she would likely sleep in her car because she didn't have money for more than one night at a hotel, said she was astonished when an anonymous donor stepped forward.
"There's someone taking care of my hotel room, [for] which I'm grateful — I don't know who, it is, but a big thank you," Mulrooney said Thursday. "The kindness is amazing."