Things to do and see on Flat Holm

Best things to do on Flat Holm Island

Unlock the secrets of Cardiff’s overlooked gem – Flat Holm Island. Nestled in the Bristol Channel, just a short boat trip away from the Welsh coast, this enigmatic island has long captured the gaze of Cardiff locals, yet its mysteries remain unexplored by many. Here we have some ideas for how to spend a couple of hours on the island – or even a couple of days.

Lying in the Bristol Channel, around four kilometres from the Welsh coast, this is an island that many Cardiff locals spend a lifetime looking at but few venture across the water to visit. Managed by Cardiff Council it is a significant nature reserve cared for by wardens and volunteers. Its gentle, grassy slope rises from the exposed rocky shore of the west to the cliffs in the east. The interior is open, flat and windswept; the island has a high point of thirty-two metres. Natural forces are not the only ones to have shaped the island’s character though. Augustinian monks, radio geniuses, Victorian gunners and the diseased have occupied it over the last 800 years and have all left their mark. Boat trips from Cardiff, timings are dependent on weather and tide, give around three hours on the island. Some operators also offer longer trips, as well as overnighters. Arrival on the island starts with a welcome from the wardens and an orientation talk. You can then join one of the tours or wander freely to explore by yourself.

RIB ride to the island

Setting off from Cardiff’s Mermaid Quay the vast lock gates of the Cardiff Bay Barrage far above your head, there is a certain apprehension at leaving the safety of the calm lagoon to enter the treacherous brown waters of the Bristol Channel. As the RIB powers towards this distant speck of rock the island features slowly reveal themselves.

Bunkers, barracks and Flat Holm’s Isolation Hospital

Any visit here starts at the old barracks, once the quarters of the gunners stationed here as part of the Victorian strategic coastal defence system. Close by, the impressive, tiled catchment area and underground storage tank is testament to the ingenuity of the Victorians who developed it as the island’s water source. To the south, the lighthouse stands on the island’s high point; its associated battery has a Moncrieff pit that housed a platform-mounted cannon that would be lowered down below ground after it was fired to protect it. The tunnels and rooms here are interesting to explore. Inland from the fossilised beach on the west coast the dilapidated building marks the site of the Victorian-era isolation hospital where ships would drop off crew and passengers suspected of carrying cholera to stop it spreading to the ports of Bristol and Cardiff. The last patient to die here was the victim of bubonic plague. Nearby, a silver plaque commemorates the first wireless transmission across open water that Guglielmo Marconi sent from Flat Holm to Lavernock Point on the south coast of Wales. 

Spot the rare wild leek

The extremely rare, purple-flowered wild leek that stands 1.5 metres tall is found in sheltered spots around the island. It only occurs in small populations in Cornwall, Somerset and Wales and flowers from June to September. The wardens ask you not to touch them.

Gulls galore

There are around three hundred pairs of herring gulls that nest here, and over three thousand pairs of lesser black-backed gulls that generally nest inland on the plateau of the island. Flat Holm’s only breeding pair of great black-backed gull, Britain’s largest gull, choose Castle Rock to nest in the north of the island. During breeding season the island becomes a frenzy of noise with many of the buildings occupied by birds and their chicks. Visitors that stray too close may be dive-bombed.

Largest pub garden in Wales

Flat Holm Island pub, The Gull and Leek, is a fine place to finish a trip to the island. Stocked with bottled beers, ciders and wines its usual winter regulars are the island’s sheep but in the summer it comes to life with daytime visitors having a quick tipple before they depart for Cardiff. The beer garden is uniquely the whole island.

Accommodation on Flat Holm Island

Staying on this wild island at night with only the wildlife, stars and twinkling lights strung along the coastline of the Bristol Channel for company is a wonderful way to appreciate its incredible location. Cardiff Harbour Authority offers organised wellness retreats on the island. Two-day stays involve yoga, reiki, reflexology and meditation sessions and vegan food and drink. Dormitory accommodation is available in the farmhouse field centre, camping in the farmhouse paddocks and the Grade II Listed Fog Horn Cottage has been converted into a self-catering cottage, offering more stylish accommodation.

Flat Holm Island walk

A two-kilometre walk around the edge of the island reveals a striking shoreline with rock outcrops, caves and rock beaches (some areas may be out of bounds during nesting season). There are plenty of opportunities to deviate inland and explore all of the historic sites on the way. See the Islandeering Route Tab