Irish Ferries is to increase its capacity on several routes to and from Ireland from next summer.
This will follow the arrival of its new 55,000 tonnes cruise ferry, the WB Yeats, currently being built in Flensburg, Germany.
It will see a doubling in the number of summer sailings between Ireland and France, offering daily departures alternatively from both Dublin and Rosslare ports.
This will also see an increase in autumn/winter sailings frequency, and an expansion in passenger, car and freight between Dublin and Holyhead.
Irish Ferries managing director, Andrew Sheen, says the plan is "to be welcomed by all interests and one that will give a significant boost to Irish tourism and trade".
"(The expansion will) give passengers and freight customers alike, more choice in terms of routes and departure dates, particularly on services to France."
When delivered in mid-2018, the WB Yeats will be the largest ferry ever to sail on the Irish Sea.
It will have space on-board for 1,885 passengers and crew and 1,200 cars.
It will have 441 cabins, an a la carte restaurant and an outside promenade deck.