Shipowner Irish Continental Group (ICG) has agreed a deal to buy a high-speed vessel known as the "Westpac Express" for $13.25 million.
The Irish Ferries owner said it expects to take ownership of the boat from current owner Bali Westpac by late May.
Upon delivery, the vessel is to be bareboat chartered to the company Sealift for a firm period of four months with four further one year option periods and a final seven month option at the charterer's option.
The Westpac Express was built in 2001 by Austal Ships. It has a gross tonnage of 8,403 tonne, passenger capacity of 900 and a car carrying capacity of 182 units.