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Puffin Island

aka Priestholm or Ynys Seiriol

Penmon, Anglesey

Location Guide


Puffin Island is an uninhabited island, and has long been unoccupied, off the eastern tip of Anglesey, and can be seen from the mainland at Penmon. It was formerly known as Priestholm in English and Ynys Lannog in Welsh. It is also shown on maps, since 1947, as Ynys Seiriol, refering to St Seiriol, who established a monastic settlement on the island and on Trwyn Du (Penmon Point) on the mainland in the 6th century. Seiriol is said to have been buried on the island. Today it is home to an important seabird colony.

It is the ninth largest island off the coast of Wales. It is carboniferous limestone, and has steep cliffs on all sides, which makes it difficult to access. It's highest point is 190ft (58m) above sea level and it covers an area of 69 acres. It is privately owned by the Baron Hill Estate and landing is not allowed without special permission.

Image of 1947 map

Puffin Island   as seen from Penmon on the mainland


It is said King Cadwallon ap Cadfan of Gwynedd sheltered on the island in around 630 when fleeing an invasion from Northumbria.

A monastery existed on the island in the late 12th century as it is known that Llywelyn the Great issued two charters in 1221 and 1237 confirming the canons regular, in possession of the island and the church and manor of Penmon on the mainland of Anglesey. The ruins of several ecclesiastical buildings are visible on the island within an enclosure. One of these, the remains of a 12th century church tower has a pyramidal roof, which is only one of two others like it, at Penmon and Llanelian.

It is said St Seiriol Gwyn (born c.494) was given the island and established a religious community there as well as on the mainland at Penmon, where there are the remains of Penmon Priory and St Seiriols Well.   There seems to be some discussion on whether he came first to the island or to Penmon. Early missionaries did tend to go to islands first, because they offered seclusion and peace and isolation, and it is thought that as St Seiriol became more popular the island could not cope with the increased number of followers and a brother colony was created on the mainland.  In old age it is thought that St Seiriol retired to the island, known then as Ynys Lannong (Priestholm) and it was renamed Ynys Seiriol in his honour.

During the middle ages monks would carry pictures of saints with them in the hope to procure food and other products. The monks here used to carry images of Saint Seiriol with 9 cheeses in his arms and these would be exchanged for wood or flour, and it was supposed to bring the farmer prosperity. At one time the inhabitants of the island are said to have caught young puffins, pickle them in barrels and then send them to England to be sold.

With the Penmon Lighthouse in the foreground

In 1841 a semaphore telegraph station was built on the north-eastern tip of the island.

Semaphore Communication System

The 18th and early 19th centuries saw a tremendous increase in the trade of the Port of Liverpool, and merchants and ship owners of the port felt they needed to know, as soon as possible, when their ships may be arriving. This led to the erection of signal houses being built, the first was erected at Bidston Hill in 1763. Flag poles were also set up, from which the house flags of the ships sighted would be flown. At one time there were over a hundred of these poles extending in a line on either side of the Signal House.

It was later decided to extend this method of signalling and Semaphore Stations were erected in commanding positions, in a number points along the coast of North Wales. By 1827 communication was established between Liverpool and Holyhead, a distance of seventy miles, via this method.

The Semaphore Station furthest away from the base was erected on the northern slope of Holyhead Mountain, Anglesey. So others were erected at strategic points including off the Anglesey coastline. By 1841 these had become a popular form of communication, that accommodation was added for signalmen and their families. This was also the year that a Semaphore Station was built on the north-east point of Puffin Island. In all between Holyhead and Liverpool there were 12 of these stations.

The most up to date type of semaphore in use at the stations consisted of two masts, each fitted with four arms, two on each side of the mast, and operated from a room below the deck upon which the masts were raised. The alphabet was represented by numbers, and the points of the compass could be given by the use of a further thirty two numbers.

The men in charge of these stations became such expert signallers that a ship owner in Liverpool would often receive the information that his vessel was off Holyhead in less than a minute from the time of her number being ascertained, while the speed of the transmission was such that the first part of the message would reach Liverpool  before the last part had left Holyhead. In a special test carried out in 1830 a message was sent out from Liverpool to Holyhead, and a reply received back in Liverpool in just twenty three seconds!

From 1860 onwards, the old semaphore system was gradually superseded by electrical transmission and many of the intermediary stations like the one on Puffin Island were closed down.

It was converted in 1887 from the Dock Board Observatory to a Biological Station, but has been in ruins since the beginning of the 20th century. Today its the only ruined building on the island along with the monastery remains that can be seen from boats that tour around the island.

Disused Semaphore Station on top  Photo by Robin Drayton

The Wildlife

Today the island is better known for it's wildlife. It is a Special Protection Area, particularly because of its Great Cormorant colony of over 750 pairs, making it one of the largest colonies in the British Isles.

At one time the island was heavily grazed by rabbits, but these were wiped out by an outbreak of myxomatosis around 40 years ago.

Puffins, from which the island gets its name today, bred in considerable numbers at one time, with up to 2,000 pairs recorded. However during the 19th century the Brown Rat was introduced, accidentally, to the island and reduced the population to just a few pairs. In 1998 the Countryside Council for Wales started an eradication programme of the rats and the Puffin population has started to increase again.

The island is also a home for thousands of guillemots and razorbills nesting on the cliffs, as well as Sandwich Terns and Eider ducks. On the far side of the island you also might glimpse grey seals.

Off the coastline the strong currents provide for an abundance of marine life, particularly on the north coast where the depths reach 15 metres. Occasionally there are sightings of bottlenose dolphins and harbour porpoises in the sea.

There is also one identified shipwreck, a steamship. The Pioneer with a cargo of iron bars, ran ashore in 1878,  when the tow lines to it broke following its rescue from engine failure near The Skerries.

A veneer of heavily guano enriched soil masks the limestone over much of the surface, leading to an impoverished vegetation dominated by a dense mat of grasses including Red Fescue and Cock's-foot, other plants include Common Nettle, Bramble, and Common Elder.

From down on the Beach

Visiting the Island

The island is not accessible, it is privately owned and is a special reserve for the wildlife only.

From Beaumaris Pier, between Easter and October, you can take a boat trip with Puffin Island Boat Cruises, which takes you around the island where you can see its seal colony, birdlife and gives you views of the Penmon Lighthouse, the trip lasting about an hour. The RSPB also run cruises on given dates between May and August, from Beaumaris Pier using a catamaran.

Alternatively for a view of the island from the mainland you can visit Penmon and it's lighthouse and get good views of it from here, as I did on my visit.

Location: Puffin Island, Penmon, Anglesey

Grid Reference: SH650820 Ceremonial County: Anglesey

Map Link: Google 

Aerial photo: Google Aerial  

Getting there: To Penmon point. From Beaumaris take the B5109 at Tre-castell take a right to Penmon. At the priory area there is a man in a box who takes a small toll and cars can continue down the single track road to the parking area at the end, where there is a small beach, cafe and the lighthouse. From here you can see Puffin Island.

Access: No access to island. Boat trips from Beaumaris take you around the island.

Other Useful Websites: Wiki   Geograph   Puffin Island Boat Cruises 

Postcode: Telephone:
Opening Times:


Nearby Locations: Penmon Priory   St Seiriols Well  Penmon Cross

Penmon Lighthouse

Other Location Pages: Anglesey Coastal Path 
Other Relevant Pages: Anglesey Attractions   Anglesey Attractions Map




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By: Tracey Park Section: Islands Section Key:
Page Ref: Puffin_Island Topic: Islands  Last Updated: 07/2014


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