Irish Ferries Holidays is offering two weeks for the price of one on cottage holidays up until June and after September. For example, stay at Glengarriff Harbour Cottages on the Beara Peninsula, Co Cork, in May, and the cost for a fortnight is £622 for two people, including ferry crossings with a car (irishferries.com/holidays).
Explore the Atlantic coast and the history and legends of Portrush, Donegal and Westport on a five-day tour from Dublin with Rabbie's Small Group Tours. The circular route costs from €290pp, including a discount (quote "St Paddy's" when booking by phone before 30 April: 0131 226 3133), plus transport and activities but not accommodation or travel to Ireland (rabbies.com).
McKinlay Kidd is offering a week-long self-drive culinary trip that takes in a visit to a smokehouse in Connemara, seafood restaurants in Co Clare and Co Kerry, and a tasting at Dungarvan Brewing Company in Waterford. From £885pp, with accommodation and numerous extras, but not travel to Ireland (seeirelanddifferently.co.uk).
Explore Ireland's railway heritage on Ffestiniog Travel's "Gathering" tour. The Gathering is a year-long celebration of Irish culture. The four-day rail tour costs from £355pp, including rail travel, B&B, and visits to various historic sites and museums. Travel to Ireland not included. Available for daily departures in May (ffestiniogtravel.com).