A total of 1.6m euro is being made available to encourage more tourists to visit and stay in counties Wicklow, Wexford and Waterford.
This EU-funded cross-border programme will also encourage tourists to visit and stay in Carmarthenshire, Pembrokeshire and Ceredigion in Wales.
The project will be developed through customer research, trade events and workshops as well as cross-border visits by businesses in Ireland and Wales to bring together expertise and ideas.
Grace Bolton of the European Commission office in Dublin says the Celtic Routes project has one key objective.
She said: "The Celtic Routes project provides €1.6m of EU funds to encourage tourists to travel to - and stay in - the counties of Waterford, Wicklow and Wexford, rather than travelling through them to get elsewhere."