Explore the national park
Mljet’s 50-square-kilometre national park’s the perfect spot for hiking and cycling, and you can rent kayaks to explore its two salt water lakes. One of them – Veliko Jezero – comes with a secret. On the tiny St Mary’s Island, which sits right in the middle of the water, there’s a former Benedictine monastery. It dates back to the 12th century, and today houses a fine-dining restaurant. An entry ticket to the park costs around £12, and includes the return boat trip to the island.