Oystermouth Castle will be one of the sites set to benefit from the funding
A £19m project to boost the contribution tourism at heritage sites makes to the Welsh economy has been announced by the assembly government.
Sites across the valleys and north and west Wales could benefit from the European and assembly government money.
By developing trails and events at heritage sites, it is hoped communities around them will benefit economically from the tourists attracted.
Heritage minister Alun Ffred Jones said he welcomed the investment in tourism.
Cadw, the government agency set up to protect the historical heritage of Wales, will work with communities, heritage partners and the tourism sector to develop a more integrated range of tours, trails and packages at heritage sites.
It is hoped this will provide benefit beyond individual sites because it will help visitors explore the surrounding towns and countryside.
Sites set to benefit include Harlech, Denbigh and Conwy castles in the north as well as attractions in west Wales and the valleys such as Oystermouth castle in the Mumbles, Swansea.
Councillor Chris Holley, Swansea council leader, said extra funding would help conserve the castle for future generations and boost visitor numbers.
"Many thousands more people will soon be discovering the mystique and magic of Oystermouth Castle," he said.
On Anglesey, the council, Cadw and enterprise agency Menter Môn are working to promote the island as a heritage tourism destination.
Councillor Bryan Owen said: "This is excellent news for heritage tourism in Wales and Anglesey in particular. We look forward to working closely with colleagues at Cadw to ensure the project is a great success and to maximise the island's potential as a heritage destination."
Heritage minister Alun Ffred Jones said he looked forward to seeing the projects and partnerships develop in the years ahead.
"Tourism is an extremely important part of our economy, contributing more than £3billion a year to the Welsh economy. I welcome this further investment in Welsh tourism," he said.