Stena Line has received the first of five new ferries from China and expects to have the vessel operating on the key Dublin to Holyhead route by January.
The Stena Estrid will be formally handed over today at the Weihai shipyard to begin its approximately 10,000-nautical mile journey to Dublin, which will take a month.
Sister ship the Stena Edda is expected to join the ferry company's Belfast to Liverpool service by late 2020, while the Stena Embla will start carrying passengers in 2021.
"Today has been six years in the planning," said Stena technical operations director Bjarne Koitrand.
"We are delighted to finally take ownership of the first of our five new ships.
"With the new crew now in place, they can start the long journey to the Irish Sea."
The 42,400-tonne ship can carry 1,000 passengers, 210 freight vehicles and 120 cars.
It will replace the Stena Superfast X, which can more passengers but less freight.
The Estrid has 3,100 metres of lanes for vehicles and the Superfast X just 1,900.
Stena said the extra capacity would allow 50% more cargo to be transported per journey.
The ship was handed over to Stena owner Dan Olsson in a ceremony that included a blessing of the vessel by a priest flown in from Hong Kong.
The Old Norse name Estrid, commonly found on Viking runestones, means 'divinely beautiful'.
The Weihai shipyard is contracted to build four more ferries for Stena, including two earmarked for use on Irish Sea routes.
"Taking ownership of Stena Estrid is a major milestone for Stena Line," said chief executive Niclas Martensson.
He added the deal "will see three of the world's most modern ferries operating between Ireland and Britain".
"Stena Estrid will provide a more environmentally sustainable way to travel, with more efficient loading and unloading, increased freight capacity and the best Scandinavian quality, style and design in our facilities," Mr Martensson said.
Stena Line operates 232 sailings weekly between Britain and Ireland, including Rosslare to Fishguard. It also links to Cairnryan in Scotland and Heysham in England.
Earlier this year the firm relocated the Belfast terminal for its Heysham service ahead of the start of work on a £15m upgrade to Victoria terminal two.
The Chinese-built boats will be capable of carrying more freight but require new infrastructure to dock in Belfast.
Co Down firm Graham was awarded the contract from the construction phase through to the installation of new ramp infrastructure.
Stena switched the service to Albert Quay, next to Clarendon Dock, for six months.