Real castles, real drawbridges-and-drum-towers stuff — Norman keeps, clifftop ruins and a royal palace, all within an hour or two's drive. Four of these ten are completely free.
What "explore" means — some of these you walk straight into: climb the keep at Carrickfergus, cross the bridge into Dunluce, wander the roofless chambers at Greencastle. At others the gardens and grounds are the day out — every entry below says exactly what you get.
Cost — Belfast Castle, Antrim Castle Gardens, Dundrum and Greencastle are free. The ticketed ruins run around £6 an adult, and Hillsborough, the royal big-hitter, starts at £11 for the gardens. Each entry links to our full guide with current prices and hours.
The ruins are the real thing.Exposed edges with sea drops at Dunluce, uneven ground and worn steps at Dundrum and Greencastle. Sturdy shoes on, small children kept close the whole way round.
Dogs & gardens — dogs on leads are welcome at Castle Ward and across Antrim Castle Gardens (which has two fenced dog parks). Belfast Castle's gardens are a no for dogs, but the Cave Hill trails around it are fine on leads.
Food — the estates feed you: tea room at Glenarm, café at Hillsborough, the old cellars at Belfast Castle, Clotworthy House at Antrim. The ruins have nothing on site — pack snacks and hit the village café after.
When — the free ruins are open sites you can visit most daylight hours all year. Glenarm runs roughly spring to autumn and Greencastle's keep opens on set summer days, so check before travelling to those two.
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Carrickfergus Castle
Carrickfergus · £6 adult, £4 child · Family £18
A great grey Norman keep rising straight out of the water on Belfast Lough — said to be one of the best-preserved Norman castles in Ireland, and 800 years old. This one you properly explore: cannons along the battery, a restored banqueting hall, figures in armour, then the climb up through the keep to the battlements and the view right across to Belfast. Pay at the gate — no online booking — and allow an hour to ninety minutes.
1–1.5 hours£6 adult · under-5s freeClosed Mondays · the keep is tight spiral stairs, no prams up top
Between Portrush & Bushmills · Around £6 adult, £4 child
The one from every postcard — a ruined medieval castle sitting on its own sea stack above the Atlantic, and yes, you cross the bridge and walk straight into it. Twin drum towers, a cove and sea cave below the rock, and a visitor centre that tells the MacDonnell story well. It's said to be one of the Game of Thrones filming backdrops. Most people do the whole site in 45 minutes to an hour, which makes it a perfect Causeway Coast stop.
45 mins – 1 hourFree parking beside the castleVery exposed cliff edges — hold small children
Hillsborough, Co. Down · Gardens from £11 · House & gardens £21.50
A working royal residence you can actually walk into — the King's official home in Northern Ireland. The Georgian State Rooms are guided-tour only, about 45 minutes, booked online with a time slot; then a hundred acres of gardens take the rest of the day, from the Walled Garden and its glasshouse to the Glen's streams and rhododendrons. Kids get the Imaginary Menagerie play trail through the grounds. One catch: it's a working residence, so the State Rooms can close at short notice.
Half a dayCafé at the Weston Pavilion · free parkingHouse is guided-tour only — book a time slot before you go
Strangford, Co. Down · NT members free · ~£13.20 adult, £6.60 child
A house with two faces — calm Classical at the front, pointed Gothic at the back, said to be down to Lord and Lady Bangor's clashing tastes — plus the cobbled farmyard Game of Thrones fans know instantly as Winterfell. In season you can even loose arrows in that same courtyard, booked separately with Winterfell Tours. Around it all: 820 acres of woodland and lough-shore trails, the Old Castle Ward tower house, a play area and cycle hire. The estate opens every day; the house runs limited days.
Half a day – full dayDogs on leads · tea-room on siteThe house runs limited days and hours — check before you go
Enniskillen, Co. Fermanagh · Modest paid entry · Family tickets
Fermanagh's castle earns its place on rainy days as well as sunny ones: a waterside fortress on the River Erne — its origins thought to date to the 15th century under the Maguire chieftains — with two museums inside one set of walls. The Fermanagh County Museum covers the county from prehistory to Belleek pottery, the Inniskillings Museum tells the story of the famous regiments, and the keep, barracks and that twin-turreted Watergate fill the gaps. Allow two to three hours.
2–3 hoursModest entry · check current pricesOpening days shift with the season — check before you set off
Straight talk on this one: Glenarm Castle is still the MacDonnell family's private home, so the interior isn't generally open — save the occasional special tour. The day out is the walled garden, said to be one of Ireland's oldest, and it's a beauty: long mixed borders, a great yew walk, kitchen garden and glasshouses, with estate and woodland walks beyond and the castle rising past the trees. Time it for a Dalriada event — Tulip Festival in spring, Highland Games in summer — and finish in the tea room.
Half a dayTea room · often a farm shopGarden & grounds only — the castle is a private home
A pale sandstone castle in the Scottish-baronial style, high on the slopes of Cave Hill with all of Belfast Lough below — and it costs nothing. The grounds and terraced gardens are free to wander, and you can step inside the castle too when it's open. Kids hunt the nine hidden cats (mosaic, stone and topiary), grown-ups take the trails up to McArt's Fort — the rocky brow known as Napoleon's Nose — and everyone meets at the coffee shop in the old cellars.
2–3 hours · half a day with Cave HillFree — grounds, castle & parkingIt's a wedding venue — the inside can close for private events
The castle itself is gone — gutted by fire in the early 1920s, in a blaze said to have broken out during a ball, with only the tower and fragments left in the grounds. The gardens it left behind are the treasure: long ornamental canals lying dead-still between towering hedges, a bright parterre, and a 12th-century motte you can climb for the view. Said to be one of the few surviving Anglo-Dutch water gardens of its kind in the British Isles — and it's completely free, no booking, walk straight in.
An easy 1–2 hoursDogs on leads · two fenced dog parksCafé & Clotworthy House keep shorter hours than the gardens
A ruined Norman castle on a hilltop above Dundrum village, with a huge round keep you can look right into and one of the finest views anywhere — Dundrum Bay, Murlough and the full sweep of the Mournes. It's a genuine ruin, not a fitted-out attraction: no ticket, no booking, no facilities, just curtain walls, a grassy bailey and that panorama. Park in the village, walk up the hill, give it an hour, then drop back down for a café stop. Free days out don't come better.
45 mins – 1 hourFree — no ticket, no bookingUphill walk, uneven ground · no facilities at the ruin
The quiet one worth the drive: a great square medieval keep with corner towers, standing right on the shore of Carlingford Lough with the Mournes at your back and the Cooley mountains across the water. It's said to date to the 1230s and thought to be an Anglo-Norman royal castle built to guard the mouth of the lough. When the keep is open you wander the roofless chambers inside; the rest of the year you can still walk the shoreline setting and view it from the outside. Give it an hour.
About an hourFree entry · no ticket officeInside the keep opens set summer days only — check before travelling
The lough run: climb the keep at Carrickfergus in the morning, then Belfast Castle after lunch — cat hunt for the kids, Cave Hill trails if the legs are fresh, coffee in the cellars either way.
The big Down day: book a morning State Rooms slot at Hillsborough, wander the gardens, then over to Castle Ward for the Winterfell farmyard and a lough-shore walk.
The free ruins day: Dundrum Castle late morning for that Mourne panorama, café in the village, then down the coast to Greencastle on Carlingford Lough — two medieval ruins, not a penny on tickets.
Keep exploring
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