Puffin Island at the North East entrance to the Menai Straits. Alas for a long time there were no puffins, they had been wiped out they say by rats who swum ashore after a shipwreck. However maybe the puffins are returning, I have seen a few close by.
There is a tempary anchorage to the east of the island when the wind is from west to northwest but you are not allowed to land.