Built in 1582 to guard Cork Harbour, Blackrock Castle has survived fires, rebuilds, and centuries of change. The round tower dates to 1600, with thick stone walls still intact.
After major fires in 1722 and 1827, it was rebuilt in neo-Gothic style by architects George and James Pain. Once used for mayoral ceremonies and civic banquets, it became a home, office, and rowing club in the 1900s.
Reclaimed in 2001, it reopened in 2007 as MTU Blackrock Castle Observatory it’s now home to astronomy exhibits, a working radio telescope, and 400+ years of history under one roof.
Visiting Blackrock Castle Observatory
Photos via Shutterstock
Although a visit to Blackrock Castle is fairly straightforward, there are a few need-to-knows that’ll make your visit that bit more enjoyable.
1. Location
CIT Blackrock Castle is in the city of Cork, 12 minutes from the city centre. The Number 202 bus service takes you there from Merchants Quay to the St Luke’s Home stop. The location is a five-minute walk from that stop.
2. Opening hours and admission
Open daily, 10:00–20:00. Last entry at 19:00. No booking required – walk-ins welcome.
3. Admission
Considering it’s one of the most popular things to do in Cork, admission is quite reasonable at:
- Adults: €9
- Students/OAPs: €7
- Children: €6
- Family (2+2): €26
The history of Blackrock Castle
Blackrock Castle began life in 1582, built to protect Cork Harbour from pirates. A circular tower followed in the early 1600s, its thick stone walls still visible today, guarding the River Lee’s entrance.
Fire, Rebuilds, and Neo-Gothic Design
The castle burned twice. In 1722, the tower was replaced by Cork’s citizens. After another fire in 1827, architects George and James Pain led a larger rebuild, adding three extra storeys and crafting the neo-Gothic look it wears today.
Civic Ceremonies and Mayoral Darts
Blackrock Castle wasn’t just defensive — it was civic. Cork’s mayor once marked the city’s authority by “throwing the dart”, a ceremony where a four-foot arrow was launched into the river every few years from a boat.
From Private Home to Public Observatory
In the 1900s, the castle became everything from a home to an office and rowing club. But in 2001, Cork City Council took it back. After major renovations, it reopened in 2007 as MTU Blackrock Castle Observatory.
A Castle That Now Looks Up
Today, it’s a science centre and observatory, offering hands-on exhibits, space-themed education, and a functioning radio telescope, proof that 400-year-old castles can still stay relevant.
Things to see at Blackrock Observatory
Photos via Shutterstock
Few castles in Ireland offer an experience as unique (or random, some might say!) as Blackrock. Here’s what to do while you’re there:
1. Explore the Castle
Blackrock Castle Observatory isn’t just about stars – it’s packed with interactive exhibitions, castle tours, and hands-on learning. There’s something new year-round, and admission includes everything.
2. Journeys of Exploration
This audio-guided experience walks you through 400+ years of castle life, from pirate raids to city defences. You’ll explore the towers, riverside terrace and gunnery while learning how this 16th-century stronghold helped protect Cork Harbour.
3. Cosmos at the Castle
This self-guided exhibit dives into life in extreme environments and how that connects to life in space. Meet Cosmo the astronaut, fire a galactic email, and explore the formation of the universe on cinema-sized screens.
4. Ireland in Space
A permanent exhibition tracing Irish links to astronomy, from Newgrange to Irish scientists at the European Space Agency.
5. The Castle Café
Set inside the castle walls, this relaxed spot serves dishes up some of the best brunch in Cork!
Things to do nearby
Now, you could follow the itinerary outlined in my Cork City guide, if you like. It’ll take you to the likes of:
- The English Market: Indoor food market since 1788, packed with local produce, butchers, fishmongers, and artisan stalls
- Elizabeth Fort: 17th-century star fort with city views, built to protect Cork from rebellion and attack
- The Butter Museum: Explores Cork’s global butter trade and the evolution of dairy in Irish life
- Saint Fin Barre’s Cathedral: Gothic Revival masterpiece from the 1800s, with sculptures, stained glass, and a towering spire
Keith O’Hara has lived in Ireland for 35 years and has spent much of the last 13 creating what is now The Irish Road Trip guide. Over the years, the website has published thousands of meticulously researched Ireland travel guides, welcoming 40 million+ visitors along the way. In 2022, the Irish Road Trip team published the world’s largest collection of Irish Road Trip itineraries. Keith lives in Dublin with his dog Toby and finds writing in the 3rd person minus craic altogether.