The nearby island, Lokrum, is reached by ferry from a jetty south of the Ploča Gate. Tourists are advised that on windy days the ferry does not make the crossing. The first to mention Lokrum in historical writings were the Benedictines, who founded a monastery there in 1023. Its ruins may still be seen today. The Benedictines brought exotic plants to the island, today a nature reserve. In 1859 Maximilian Habsburg built a mansion there, surrounded by beautiful gardens with the marvels of the world's flora. One hundred years later a botanical garden with South American and Australian plants was established on the island.

Another feature of the island is a small lake with an outlet to the sea. Its water is calm and crystal clear, suitable for swimming. In 1806, two years before their conquest of Ragusa, the French built Forte Royale, a star-shaped fortress, at the island's highest point (91 m.), thus giving us a magnificent view of the island and the city, ten minutes away.