Lokrum is a 700-metre ferry ride from Dubrovnik's old port, a densely wooded island of cypress, rosemary, and subtropical gardens just offshore. The 15-minute ferry runs regularly in summer and the island is a popular escape from the crowds inside the walls — no cars, no permanent residents (except the monks' feral peacocks), and several good swimming spots off the rocky eastern coast.
The monastery ruins and botanical gardens in the interior are pleasant to wander through. The saltwater lake (Mrtvo More, or Dead Sea) in the centre of the island is excellent for swimming without the waves. The fort on the highest point gives panoramic views of Dubrovnik and the coast. There are a couple of simple restaurants and a kiosk on the island; bring water and sun protection.