There are 7 islands: Caldey Island, Grassholm, Middleholm, Ramsey Island, Skokholm, Skomer and St Margaret’s Island. It’s believed all were inhabited in prehistoric times and most were farmed well into the 20th century. However, all except Caldey are uninhabited now, although many are nature reserves with wardens present.
Skomer, Ramsey and Caldey are the most accessible islands, with daily boat trips from the mainland between Easter and October, but the others can be seen up close from a boat.
Skomer, Skokholm and Grassholm are a trio of neighbouring islands grouped together as a Site of Special Scientific Interest, for their populations of puffins, Manx shearwaters and gannets.
In contrast, Caldey Island is a charming little island off the coast of Tenby, complete with a Cistercian monastery. The monks make and sell their own lavender perfume and shortbread and you can purchase their own postage stamps and currency in the post office.