The SeaCat ferry service between Belfast and Troon is to end, the company has said.
Trading losses are being blamed for the crossing being axed
Spiralling fuel costs and competition from budget airlines have been blamed for trading losses.
SeaCat said about 45 jobs will go but it is hoped many of the staff will be redeployed within the company.
SeaCat general manager Diane Pool said: "It is a sad day for SeaCat, who pioneered fast ferry travel on the Irish Sea in 1992."
The Belfast to Troon service has operated between March and October, and employs 45 people, 41 in Belfast and four in Troon.
However, the future of the crossing had been under threat for some time, despite the growth of tourism to Northern Ireland.
Ms Poole said trading losses had become unacceptable and the company had no option but to close the operation.
She said the travel industry had undergone immense change since SeaCat began its operations.
"As a dynamic company, we are proud of the huge contribution we have made to tourism and the Northern Ireland economy," she said.
Last year, the service carried 302,656 passengers and 72,876 vehicles.