BOAT-COMPARATOR Guide

Mljet by Boat: Croatia’s Salt-Lake National Park, Between Dubrovnik and Korčula

Two saltwater lakes linked to the sea, a Benedictine abbey on a tiny islet, harmless resident jellyfish to swim among: the guide to visiting Mljet National Park on a rented boat.

Between Korčula and Dubrovnik, the island of Mljet stays remarkably clear of the crowds that swamp the rest of southern Dalmatia every summer. The reason comes down to one figure: nearly a third of the island, its western half, has been a national park since 1960 — one of the oldest protected areas in the Adriatic — and it's best explored almost entirely by sea.

Two salt lakes inside a pine forest

The heart of the park is two saltwater lakes, Veliko Jezero ("great lake") and Malo Jezero ("small lake"), formed from old karst depressions flooded by the sea thousands of years ago. Linked to each other by a narrow channel and to the open sea by the Soline channel, they make up a calm, turquoise stretch of water ringed by Aleppo pines — a sharp contrast with the swell that can build off the island's exposed southern coast. A roughly 9 km walking and cycling trail loops around both lakes for anyone who wants to step ashore for a while.

The islet of St Mary and its monastery

In the middle of Veliko Jezero sits a tiny islet, Sveta Marija, home to a Benedictine monastery founded in the 12th century and its Romanesque church. It's reachable only by boat — a park shuttle, included in the entrance ticket, runs continuously from the jetties around the lake. Set aside the best part of an hour to see the church, the cloister and the café in the former refectory.

Getting to Mljet on a rented boat

Mljet sits roughly 29 nautical miles from Dubrovnik and just 14 miles from Korčula, making it a natural stop on any itinerary linking the two. Two bays serve as gateways into the park: Polače, to the north-west, and Pomena, right next to the mouth of the Soline channel. Once inside the channel and out onto Veliko Jezero, speed is capped at 5 knots for every vessel — a reminder that this stretch of water is first and foremost a protected natural area, not just another anchorage.

An entrance ticket that applies to private boats too

Unlike a land-only visit, navigating the park's waters on a rented boat requires a vessel entrance ticket, separate from the on-foot adult ticket: it's priced by the boat's length and the season, and checked at sea by park rangers. Budget roughly €20-30 for an adult on-foot ticket in high season, noticeably less in spring and autumn — exact rates shift year to year, so it's worth checking the park's official site before setting off. The ticket includes the shuttle across to Sveta Marija.

The lake's resident jellyfish: a harmless curiosity

Swimming in Veliko Jezero can spring a small surprise: the lake hosts a resident jellyfish population, mostly the Aurelia species (moon jellyfish), which thrives in water that's warmer and richer in nutrients than the open sea nearby. An eighteen-month study of Mljet's saltwater lakes documented this jellyfish population alongside the broader ecological quirks of these semi-enclosed waters, notably more eutrophic than the oligotrophic open-Adriatic ecosystem around them (Benović, Lučić, Onofri, Peharda & Carić, Scientia Marina, 2000, see the study on Google Scholar). No need to worry: these moon jellyfish carry only a very mild sting, barely noticeable to humans — an encounter worth watching rather than fearing.

Where to anchor: Polače and Pomena

Anchoring is concentrated in two marked zones: Lokva bay, at Pomena, and Luka Polače bay, both within precise limits set by the park — dropping anchor outside these areas isn't part of the plan. As in any protected area, discharging grey or black water is banned both at berth and at anchor; our guides to marine protected areas in the Mediterranean and to anchoring etiquette cover the ground rules that apply here just as everywhere else.

Pairing Mljet with Korčula or Dubrovnik

Its closeness to Korčula makes Mljet an easy half-day stop to slot into a week-long charter around southern Dalmatia, while from Dubrovnik it's worth setting aside a full day to enjoy the lakes without rushing. A fast RIB (€200-600 a day) covers the round trip from Korčula with no trouble; a sailboat or catamaran chartered for the week (€300-700 a day) allows for a night at anchor in Polače or Pomena before continuing on toward Dubrovnik or the Elaphiti Islands. On the same boat, Boat-Comparator compares live offers from Boataround, SamBoat, Click&Boat and GlobeSailor side by side: a 10-25% gap between platforms is common on this in-demand stretch of Dalmatia.

Our advice

Book your entrance ticket ahead of time where that's an option, aim for a morning arrival at Polače or Pomena to enjoy the lakes before the midday rush, and leave time for the walking or cycling loop around Malo Jezero, usually quieter than Veliko Jezero. Our guides to Korčula and to Dubrovnik and the Elaphiti Islands help build the full itinerary, and the Dubrovnik and Korčula pages round up the offers available on Boat-Comparator, with no affiliation to any platform.

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