Puffin Island

Fri 17th August 2018

Puffin Island or Ynys Seiriol is an uninhabited island off Penmon Point and the eastern tip of Anglesey.  Historically the puffin population had been decimated by rats. Steps taken to remove the rats, in 1988, enabled the puffins to slowly return. Sea birds fill the sky during the early summer months and the large seal population haul out on the rocky shoreline on a dropping tide.

Puffin Island Ynys Seiriol

The island has has a number of names; called Priestholm by the Vikings and Ynys Lannog by the Welsh. It is was also referred to as the Isle of Glannauch/Ynys Glannauc or Ynys Lenach, the Priest’s Island. It is believed that 18th contrary sailors dubbed the name Puffin Island due to the large colony of sea birds.

A hermitage was established on the island in the 6th century by Saint Seiriol, hence the name Ynys Seiriol, Seiriol’s Island. A monastery existed on the island until the 12th century. This monastery was linked to the Augustine Priory at Penmon. There are ruins on the island that include a tower of a 12th Century church with a rare Norman style pyramid shaped roof. Other ruins are covered by the remains of a 19th-century cottage.

The island is uninhabited now and visitors can’t step foot on the island. It has become a home to sea birds and seals. It is a Special Protection Area which provides EU directive to protect wild birds. There are a number f research projects which monitor the birdlife on the island

Ynys Seiriol Puffin Island Bird life

  • black guillemot
  • common eider
  • cormorant
  • european shags
  • fulmar
  • great black-backed gull
  • guillemot
  • herring gull
  • kittiwake
  • lesser black-backed gull
  • puffins
  • razorbill

A Puffin flying over the Skerries, RibRide

The Seals

There is a large colony of great seal at Puffin Island. Grey seals and common seals share the waters around Anglesey. The grey Seals are much larger with a pronounced ‘Roman’ or hooked nose. Autumn is a great time to go out spotting grey seals and their new pups.


Harbour porpoises and bottlenose dolphins regularly visit the area. This year a large pod of common dolphins were spotted in the Strait near Puffin Island, it was a special spectacle.


You can take a trip to see the seals (and puffins in the early summer) by taking a ‘Puffin and Seals’ trip to Puffin Island/Ynys Seiriol. The trip is 1.5 hrs long and goes past the beautiful town of Beaumaris before reaching Penmon Point and the light house Trwyn Du at Puffin Island/Ynys Seiriol.

More information on this RibRide trip can be found at ‘Puffin and Seals‘.