The Jonathan Swift made its first scheduled voyage from Dublin to Holyhead on Saturday after ship's officers at Irish Ferries voted almost unanimously to accept proposals to resolve a staffing dispute.
Under the terms, brokered by the IBEC director, Mr Turlough O'Sullivan, and the SIPTU regional secretary, Mr Jack Nash, the officers have retained leave entitlements operating on the company's slower ferries while conceding greater flexibility.
The SIPTU branch secretary, Mr Brian Fitzgerald, said his members "got a good deal, and one the company can live with."
During the two-week dispute, the £29 million Jonathan Swift was tied up in Dublin. The company had threatened to sell it or charter it out while SIPTU had threatened an all-out strike.