Brittany Ferries is moving its Ireland-Spain sailings from Cork to Rosslare Europort, with the first sailing due to take place on February 28.
It said the new Spanish arrival port from Rosslare would be Bilbao.
"This was not a decision we took lightly and follows extensive consultation with our freight customers who sought better road connections and reduced driving distances," said Christophe Mathieu, Brittany Ferries CEO.
"We opened the route in 2018 with a two-year trial window. While passenger numbers have been encouraging, the reality is that freight numbers, which are key to route viability, were not sufficiently robust.
"However, I want to make it clear that we remain committed to Cork, with our flagship Pont-Aven cruise-ferry service to Roscoff. We're also committed to an Ireland-Spain route, now via Rosslare, and we'll look after existing passengers whose future travel will be affected by this change."
The company said that all customers already booked on affected sailings from Cork would be given the option to transfer their booking to sailing between Rosslare and Bilbao/Roscoff.
An allowance will be given to cover additional transfers. Alternatively, a full refund will be provided to those who choose to cancel.
Glenn Carr, general manager of Rosslare Europort, said: "We are delighted to welcome Brittany Ferries to Rosslare Europort. This new Rosslare to Bilbao service will be attractive for trade and tourism alike. We very much welcome that this service is being launched because of demand from freight customers, due to Rosslare's strategic position and access to key markets. Brittany Ferries will also benefit from our €25m investment in port facilities, infrastructure and technology."