Mljet day trip from Dubrovnik: national park, lakes, and monastery

Mljet: Croatia’s greenest island

Mljet is one of the most beautiful islands in the Adriatic and one of the least like anywhere else near Dubrovnik. Where the Elaphiti islands are compact and approachable, Mljet is long, forested, and genuinely wild in its western national park section. Dense Aleppo pine covers most of the island. The two saltwater lakes — Malo jezero (Small Lake) and Veliko jezero (Big Lake) — sit in the pine forest like something from a Nordic landscape accidentally relocated to the Mediterranean.

The 12th-century Benedictine monastery on a small island in the middle of Veliko jezero completes a picture that is, by any standard, exceptional.

Getting to Mljet from Dubrovnik

Ferry and catamaran options

The main departure point is Dubrovnik’s Gruž port. Several services cover the route:

Jadrolinija ferry (year-round): Car ferry to Sobra on Mljet, approximately 1.5 hours. Sobra is the main port but is not inside the national park — from Sobra you’ll need a local bus or taxi to reach Polače or Pomena, the villages closest to the national park entrance.

Summer catamarans (Krilo, Jadrolinija): Faster passenger-only services, some of which call at Polače directly. Journey times around 2 hours. These are the most convenient for day trips in summer.

Check Dubrovnik ferries and catamarans for current timetables and booking. In summer, popular catamaran services fill up — book ahead.

Organised day tour

Guided day trips to Mljet are available from Dubrovnik, covering transport, park entry, and a guided walk around the lakes.

Mljet National Park guided day trip from Dubrovnik

Malo and Veliko jezero: the saltwater lakes

The two lakes are the heart of the national park. Connected to each other and to the sea through a narrow channel, they maintain near-sea salinity and are excellent for swimming. The water is clear and calm — protected from the open Adriatic by the surrounding pine forest — and warm by late June through to late September.

Malo jezero (Small Lake) is the more intimate of the two, with a shoreline path through pines and a small beach near the entrance. Good for a quiet swim away from the larger crowds.

Veliko jezero (Big Lake) is the larger lake and the main focus of the park. The circular walking trail around it takes about 2 hours at a relaxed pace. A boat service (included in the park entry fee) crosses to the island monastery in the middle of the lake.

St Mary’s Island and the Benedictine monastery

The small island of St Mary (Sveta Marija) in the middle of Veliko jezero is home to a Benedictine monastery founded in the 12th century. The current buildings are partly medieval and partly later; the church and cloister are the most interesting elements. The monastery has had a varied history — it was a Benedictine foundation, then a hotel in the Yugoslav era (the cloisters served as a café), and is now in the process of being returned to religious use.

The boat from the lake shore takes about 5 minutes. Combined with a walk around part of the lake shore and a swim, the monastery visit makes for a very complete couple of hours in the park.

Walking and cycling in the park

The national park has well-maintained paths around both lakes and through the surrounding forest. Bicycles are available to rent at the park entrance (included in the basic park fee or at modest extra cost). The full circuit of Veliko jezero by foot takes about 2 hours; by bicycle, faster. The terrain is mostly flat through pine forest with occasional lake views.

For walkers, the path around the lakes is the main route. More challenging walks on the forest hills above the lake exist but require a trail map from the park office.

The eastern part of Mljet

The national park covers only the western third of the island. The eastern part — including the village of Babino Polje (the administrative centre), the small town of Saplunara with its sandy beach at the southeastern tip, and the village of Blato — is accessible but requires transport and is rarely covered on day trips. Saplunara beach is genuinely beautiful and worth the extra effort if you’re staying overnight.

Where to eat near the national park

Polače: The small village next to the national park entrance has several konobas serving fresh fish and pasta. Simple, reasonable, and aimed at park visitors. Restaurant Melita on the waterfront is the most established.

Pomena: A slightly larger village on the western bay, with boat access from the lakes. A few restaurants and the Hotel Odisej (which also has a restaurant).

Avoid bringing a large amount of food into the park — the point of the visit is the lakes and forest. Lunch at one of the Polače waterfront konobas after swimming is the natural rhythm of a day trip.

Practical notes

• Book ferries in advance: Summer catamarans from Dubrovnik to Mljet fill up, especially on weekends. Book at least a day ahead.
• Park entry: Buy at the park entrance at Polače. Credit cards accepted. The fee includes the lake boat and bicycle rental.
• What to bring: Swimming gear, water shoes (the lake shores are pebbly in places), sunscreen, water. There is no shade on the lake boat crossing.
• Best season: June, July, and September. July–August is busy but the lake swimming is at its best. May is quieter; ferry schedules are reduced.
• Last return ferry: Check the return catamaran time carefully. Missing the last boat from Mljet means an unplanned overnight.

Frequently asked questions about Mljet day trips from Dubrovnik

Is Mljet better than the Elaphiti Islands for a day trip?

Different experiences. Mljet is more dramatic and offers genuine nature — the national park, forests, and saltwater lakes are unlike anything in the Elaphiti chain. The Elaphiti Islands (Lopud, Šipan, Koločep) are more accessible, more varied, and include the finest sandy beach near Dubrovnik (Šunj on Lopud). Mljet suits travellers who want a nature-focused, relatively tranquil day. The Elaphiti are better for island-hopping variety.

Is the monastery still a working religious site?

Partially. After decades as a hotel in the Yugoslav era, the monastery has been gradually returned to religious use. Not all parts are open to visitors, and the situation has evolved over time. As of recent visits, the church and parts of the cloister are accessible.

Can I take a car to Mljet?

Yes — car ferries to Sobra run year-round. If you want maximum flexibility to explore the eastern part of the island, taking your car is worthwhile. For a day trip focused on the national park, a car is not necessary; the park entrance is close to the Polače dock.

What is the water temperature in Mljet’s lakes?

The saltwater lakes warm up to 24–27°C by late July and August — warmer than the open sea in places because they are sheltered. By September they are still comfortably above 22°C. May and early June can be cooler but still swimmable.

Is Mljet suitable for young children?

Yes. The lakes are calm and well-suited to children. The main walking path is flat. The boat to the monastery island takes 5 minutes. The main consideration is sun protection — the lake shore has limited shade in summer.