Ranked by strength
The 10 strongest castles in Wales
Wales’s mightiest fortresses — the strongholds built to hold against siege, ranked by military strength rather than fame. Each links through to its full history, and you can rebuild any of them to explore with AI.
- 1
Wales · Restored · prime 1330
Caernarfon Castle
Caernarfon Castle is a large late 13th–early 14th century Edwardian fortress on a peninsula by the River Seiont in north‑west Wales. Built as the administrative centre of north Wales, its surviving fabric consists largely of high curtain walls and many multi‑sided towers that link into the town walls and quay.
- 2
Wales · Ruin · prime 1287
Conwy Castle
Conwy Castle is a late 13th-century Edwardian fortress in north Wales, constructed between 1283 and 1287 as part of a new walled town. The rectangular stone castle has eight large drum towers, two barbicans and inner and outer wards, and occupies a rocky coastal ridge overlooking the River Conwy. Today the ruin is managed by Cadw and is part of the Castles and Town Walls of King Edward in Gwynedd World Heritage Site.
- 3
Wales · Partial ruin · prime 1330
Beaumaris Castle
Beaumaris Castle is a late 13th–early 14th century concentric castle on Anglesey, Wales, begun under Edward I and designed by James of St George. It consists of an outer moated ward with multiple towers and gatehouses surrounding a larger inner ward intended to contain domestic ranges; the site later fell into ruin and is now a maintained historic monument and tourist attraction.
- 4
Wales · Restored · prime 1326
Caerphilly Castle
Caerphilly Castle is a large medieval concentric castle in Caerphilly, South Wales, built in the late 13th century by Gilbert de Clare. It occupies a central island surrounded by extensive artificial lakes and multiple rings of curtain walls and towers and contains a Great Hall and substantial gatehouses.
- 5
Wales · Restored · prime 1280
Pembroke Castle
Pembroke Castle is a medieval Norman enclosure castle sited on a rocky promontory beside the Milford Haven waterway at Pembroke, Wales. Rebuilt in stone by William Marshal from 1189 and enlarged through the 13th century, it features a huge circular keep, inner and outer wards, and a twin-towered gatehouse. It is a Grade I listed building, was extensively restored in the 20th century, and remains open to the public as a privately managed castle.
- 6
Wales · Partial ruin · prime 1284
Chepstow Castle
Chepstow Castle is a Norman stone castle on a narrow ridge above the River Wye in Monmouthshire, Wales, founded soon after the Conquest and expanded through the 12th–13th centuries. Its plan shows multiple baileys with a large Great Tower, round towers on the landward side and a prominent gatehouse; many of the standing walls and towers survive as substantial masonry. The site is historically important as an early stone border stronghold in the Welsh Marches.
- 7
Wales · Partial ruin · prime 1300
Denbigh Castle
Denbigh Castle is a late 13th‑century concentric fortress built on a wooded hill above the town of Denbigh in north‑east Wales. Its entrance is dominated by a triangular complex of three octagonal towers and long curtain walls with multiple mural towers that connect into the town defences. The site survives as extensive stone ruins of walls, towers and the inner ward.
- 8
Wales · Partial ruin · prime 1200
Kidwelly Castle
Kidwelly Castle is a Norman stone castle overlooking the River Gwendraeth and the town of Kidwelly in Carmarthenshire, Wales. The surviving plan centres on a square inner bailey with four round towers and a semi-circular outer curtain wall on the landward side, with a large gatehouse sited beside the river.
- 9
Wales · Partial ruin · prime 1282
Rhuddlan Castle
Rhuddlan Castle is a late 13th-century concentric fortress on the River Clwyd in north‑east Wales, begun by Edward I and chiefly built under master mason James of Saint George. Completed in 1282, it formed part of Edward's ring of Gwynedd fortifications and features a distinctive diamond layout with gatehouses placed at the corners. The site is now managed by Cadw and survives as substantial medieval masonry remains.
- 10
Wales · Partial ruin · prime 1639
Raglan Castle
Raglan Castle is a late medieval fortified residence in Monmouthshire, Wales, developed between the 15th and early 17th centuries by the Herbert and Somerset families. It combined strong polygonal towers and curtain walls with extensive gardens, water features and grand domestic ranges. The castle was besieged and deliberately slighted in 1646 and thereafter partly quarried; today it survives as a substantial romantic ruin and tourist site.