Herm is tiny — a mile and a half long and half a mile wide — and entirely car-free. It sits three miles east of St Peter Port, Guernsey, and the fast catamaran crossing takes about 20 minutes. Around 60 people live here year-round; in summer day-trippers arrive to walk the clifftop paths, swim off Shell Beach on the north end, and eat at the island's single pub, the Mermaid Tavern.
There are no crowds in any meaningful sense. The island is privately leased from the States of Guernsey and managed as a single estate. There is a small shop, a pub, and an 11th-century chapel. That is more or less everything.
Shell Beach itself is worth the trip — the beach is composed almost entirely of broken shells carried in by the Atlantic rather than sand, and the water in summer is clear and relatively warm. The southern cliffs offer views across to Sark and the private island of Jethou. If you are based in Guernsey and looking for a quiet half-day, Herm is an easy and rewarding excursion.