Getting Between Stops
You need a rental car for this route. Buses serve some towns, but castles, cliffs and beaches are spread out.
Shannon to Clifden is about two and a half hours. Clifden to Donegal Town is about three and a half hours via Westport and Sligo. Donegal to the Causeway Coast is about two to two and a half hours. The Causeway Coast to Dublin Airport is about three hours.
Ireland drives on the left. Roads in Connemara and Donegal are narrow and winding, with sheep on the road in places, so allow more time than the map suggests. An automatic car is worth the extra cost if you are not used to a manual.
Driving between the Republic of Ireland and Northern Ireland is straightforward. Rental companies may charge a cross-border fee, so mention your plans when booking. Speed limits switch from kilometers to miles at the border.
Where to Stay
In Connemara, Ballynahinch Castle sits among woods on a river and lake east of Clifden, with a lively bar and warm service. Ashford Castle in Cong, just inside County Mayo, is one of Ireland's most famous luxury hotels, with falconry and a lakeside estate. Renvyle House, on the coast near Letterfrack, is a historic country house with sea views.
In Donegal, Lough Eske Castle near Donegal Town is the county's most polished splurge, with a spa on wooded grounds. Harvey's Point, on the same lake, is a long-running favorite with a lakeside restaurant. Rathmullan House, on Lough Swilly, is a family-run country house with gardens to the beach.
On the Causeway Coast, the Bushmills Inn is an old coaching inn with peat fires. The Causeway Hotel sits beside the World Heritage Site, so you can walk down before day visitors arrive.
When to Go
May to September is the best time. Days are long, with daylight past 10 p.m. in June. Late May and June bring wildflowers, puffins on Rathlin Island and lower prices than July and August. September brings heather on the hills and quieter roads.
July and August are the busiest months, with higher prices and more traffic at the Giant's Causeway. Book castle hotels well ahead.
Irish weather is changeable in any month. Expect rain, wind and sunshine, sometimes in one afternoon. Pack rain jackets and waterproof shoes.
From October to April, days are short and many smaller hotels close. Castle hotels stay open and are cozy in winter, but outdoor sights are less enjoyable and some ferries stop running.
What It Costs
Castle hotels are the big cost. As an approximate guide, Ballynahinch Castle starts around $400 a night for two, while Ashford Castle costs much more. Lough Eske Castle and other country-house hotels in Donegal run roughly €150 to €350. On the Causeway Coast, good doubles cost about £120 to £280, rising around big golf events.
The Republic of Ireland uses the euro and Northern Ireland uses the pound sterling. Cards work everywhere.
A rental car for ten days, fuel and any cross-border fee add up, so book early for the best rates on automatics.
The things worth paying for are at least one night in a castle hotel, a Killary Harbour cruise, a Bushmills tasting and a links golf round for golfers. Pub dinners and trad music sessions are good value.
Tips for the Two of You
Pack for rain. Waterproof jackets, shoes with grip and warm layers matter more than anything else.
Cliff walks at Sliabh Liag and the Causeway are beautiful but exposed. Stay on marked paths, keep well back from edges in wind and check conditions before setting out.
Atlantic beaches look inviting, but the water is cold and currents can be strong. Swim only at lifeguarded beaches in summer.
Share the driving if you can. Narrow roads and long days are easier with turns at the wheel.
The route serves different tastes. One of you might play golf at Portrush while the other walks the beach or tours a distillery. In Donegal, one might hike while the other books a castle spa afternoon. Meet by the fire for dinner. Trad music sessions in pubs are informal, so ask locals where and when.
Make It Shorter or Longer
With a week, skip Donegal and drive from Connemara to the Causeway Coast, about four and a half to five hours, or fly into Dublin and focus on Donegal and the Causeway Coast.
With 12 or 13 days, add two nights in Dublin at the start or end for the city's pubs and museums. Or add County Clare and the Cliffs of Moher, close to Shannon, for two nights before Connemara.
Another option is to add Belfast for a night between the Causeway Coast and Dublin, with the Titanic museum and the Cathedral Quarter.
Couples who want Scotland too can take the ferry from Belfast to Cairnryan, then drive to the Scottish Highlands and Isle of Skye for a castle-to-castle trip across two countries.
