Mljet National Park: Croatia's Greenest, Gentlest Island

There is a moment, about ten minutes after the catamaran leaves Dubrovnik behind, when the Adriatic simply empties out. The cruise ships vanish, the coastline softens, and ahead of you a long, low island appears, covered from end to end in dark pine forest. That is Mljet — and its western third has been a national park since 1960, which makes it the oldest marine protected area in the Mediterranean.

Mljet is not a place of big sights. It is a place of two green-blue saltwater lakes, a tiny islet with a medieval monastery in the middle of one of them, a Roman ruin on a sleepy waterfront, and the smell of warm pine resin. Nothing shouts. Everything invites you to sit down.

It is also, we think, one of the kindest nature destinations in Croatia for travelers who would rather not climb things. Cars are kept away from the lakes, so the shoreline belongs to walkers, small electric boats and a little open-sided train. You can see the heart of this park beautifully without ever going uphill.

A little history

People have been quietly making a living on Mljet for a very long time. On the waterfront at Polače stand the walls of a large Roman palace, thought to date from around the 5th century — so substantial that the village road now runs straight through the middle of it. It is considered one of the biggest and best-preserved Roman structures in Dalmatia, after Diocletian's Palace in Split and the arena in Pula.

The island's most photographed building came later. In 1151 Benedictine monks were invited to Mljet by Desa, a local duke, and settled on the islet of St Mary in the Great Lake. They added a church beside the monastery in the second half of the 12th century, then rebuilt and fortified the whole complex over the 15th and 16th centuries, giving it the squat tower and thick walls you see today. The monastery closed in 1809, during the brief French rule of the island; it served as a hotel between 1960 and 1991, and in 1998 it was returned to the Diocese of Dubrovnik.

One more curiosity: in 1910 a handful of small Indian mongooses were released on Mljet to control the island's horned vipers. The vipers are now very scarce — and the mongoose, improbably, is still here. If something slim and quick crosses the path in front of you, that is what it was.

Aerial view of St Mary Island in Mljet National Park.

What to see

The park covers roughly 5,300 hectares, about a third of the island, and almost everything a first-time visitor comes for is gathered around the two lakes.

Veliko and Malo Jezero, the saltwater lakes

They are called lakes, but they are really flooded bays, linked to the open sea by narrow channels — which is why the water is salty, startlingly clear, and warmer than the sea outside by late summer. Veliko Jezero (the Great Lake) is the larger and deeper of the two; Malo Jezero (the Small Lake) sits just behind it, reached by the little bridge known as Mali Most. Pines come right down to the water, and the colour shifts through the day from jade to deep ink-blue.

St Mary islet and the monastery

A short boat ride from the shore brings you to the islet in the middle of Veliko Jezero. The return crossing is normally included in the park ticket. On the islet there is the monastery and church, a terrace café under the trees, and a flat loop of a few hundred metres around the shoreline. It is the single loveliest place on Mljet to do nothing at all.

Polače and its Roman walls

Polače is a sheltered, yacht-filled bay with the Roman palace standing right on the quay. Flat, shaded, with a handful of konobas — an easy stop while you wait for a boat.

Montokuc, the big view

The park's best-known viewpoint rises above the Great Lake, with both lakes, the forest and the open Adriatic laid out below. Be honest with yourself about this one: it is a stony uphill path of roughly 200 metres of ascent and, allowing for stops, two to three hours there and back from Pomena or Pristanište. Wonderful if your knees are willing; entirely skippable if they are not, because the lakeside views are glorious at sea level.

Pomena and the quiet shore

Pomena, the little harbour at the western tip, is barely more than a row of houses, a hotel and fishing boats. Walk ten minutes out of it in either direction and you will hear nothing but cicadas.

St Mary Island in Mljet National Park, seen across the Great Lake.

The comfortable ways to see it

This is where Mljet quietly excels. The park has deliberately kept traffic away from the lakes, and replaced it with slow, sit-down transport.

Small boats

Shuttle boats run in a loop between Pristanište, St Mary islet and Mali Most through the season, roughly every half hour at busy times. Boarding is from low jetties and the crossings are only minutes long on sheltered water, so even nervous passengers tend to be fine. Used cleverly, these boats let you cross the park in one direction and sail back in the other, with no retracing of steps.

The electric train

In the main season an open electric train runs along the shore of the Great Lake. It is not fast and not glamorous, and that is exactly the point: you sit, the pines slide past, and you cover in fifteen minutes what would otherwise be a long warm walk. Services usually start in spring and finish in late September, so check locally if you travel in the shoulder months.

Gentle walks

The path around Malo Jezero is the one we recommend most often: about 3 to 4 kilometres of level, well-made shoreline track, mostly in shade, with benches and swimming spots. Allow an unhurried hour and a half. The full circuit of the Great Lake is far longer — think 9 to 10 kilometres — and best broken up with a boat or train leg rather than walked whole.

Bicycles and e-bikes

Bikes can be hired in Pomena, Polače and at the park entrances, and the lakeside tracks are closed to cars, which makes cycling here unusually relaxed. The island has real hills, though, so if you are tempted, take an e-bike and let the motor do the arguing.

Boat trips

Small-boat excursions along the coast are the comfortable way to reach places a footpath would punish you for, including Odysseus Cave on the island's southern shore — the sea cave where, by local tradition, Odysseus was held by the nymph Calypso.

Forested shoreline and clear water in Mljet National Park.

A day trip nearby

If you are staying more than a night or two, give a day to the eastern half of Mljet, outside the park. It is a different island: fewer visitors, olive terraces, and at the far end Saplunara, where you will find the rare thing in Croatia — soft sandy beaches with shallow, gently shelving water, backed by pine woods.

The drive or taxi ride along the island's single spine road takes roughly an hour from the park, with a few long views out to sea on the way. En route, the village of Babino Polje is the usual starting point for Odysseus Cave; the walking route down is steep and rough, so we would take the boat instead and simply admire the cave from the water.

Many of the fast catamaran lines that serve Mljet continue towards Korčula, so a day in Korčula town is possible on some schedules — but the timetables change from season to season, so confirm the return sailing before you commit to it.

The island of Mljet in spring.

Honest advice for comfortable travel

• Stay inside or beside the park. Pomena and Polače both put you within a short, flat walk of the lakes and the boat jetties. If you land at Sobra, you are still on the eastern side of the island and need around 45 minutes of road transport to reach the park — fine once, tiring daily.
• Buy the park ticket that includes the boat. The standard visitor ticket normally covers the return crossing to St Mary islet and the electric train according to its timetable, which removes a lot of small decisions.
• Combine, don't loop. Walk one short stretch, then ride the boat or train back. Walking a full lake circuit in July heat is the commonest mistake we see.
• Heat is the real difficulty, not the terrain. July and August regularly climb into the low to mid thirties Celsius. Be out before 11am, rest at midday, and carry more water than feels necessary.
• Footwear matters more than fitness. The lakeside tracks are firm but gravelly, and stone surfaces near the monastery can be slippery when wet. Closed shoes with grip, not sandals.
• Jetties, not gangways. Boarding the catamaran from Dubrovnik and the small park boats involves a step down or across, sometimes with a slight sway. Accept the crew's hand; they offer it all day long.
• Not a wheelchair destination overall, though the flat waterfronts at Pomena and Polače and the shoreline track near Mali Most are manageable for someone who walks slowly or uses a stick.
• Decide in advance between a day trip and a stay. A day trip from Dubrovnik gives you roughly five to six hours on the island; staying over gives you the lakes at dawn, which is when they are at their most beautiful.
• Bring some cash for the small places. Croatia uses the euro and cards are widely taken, but island konobas and boat hires sometimes prefer notes.

Mljet National Park early in the morning.

What to eat

Island food here is simple and done well. Fish and shellfish come off local boats; grilled whole fish with olive oil, garlic and chard-and-potato blitva is the classic plate, and it appears on almost every menu around the lakes.

The dish worth planning for is peka — meat or octopus baked slowly under a domed metal lid buried in embers, so everything emerges soft and smoky. It usually needs ordering several hours ahead, so ask when you arrive rather than when you are hungry. Goat and lamb are island staples too, and lobster appears on the smarter menus in summer.

Mljet's other pride is olive oil, pressed from groves that have been worked for centuries, and Dalmatian wines — crisp white Pošip, dark and generous Plavac Mali. Finish, if you are offered it, with a small glass of homemade grappa; refusing is possible but mildly disappointing to your host.

One practical note: the restaurants are clustered in Pomena, Polače and Soline, with a café on St Mary islet. Elsewhere in the park there is very little, so carry fruit and water on walks.

Getting there

If you only have one day, sail to Polače or Pomena rather than Sobra — both drop you within walking distance of the park gates.

Our verdict

Mljet is the antidote to Dubrovnik. Where the old city gives you crowds, marble steps and midday heat trapped between walls, Mljet gives you shade, water, benches and silence. For travelers over 60 who want nature without negotiation, it is close to ideal: the finest views are at lake level, the transport is designed for sitting down, and the one strenuous climb is entirely optional.

Go for two nights if you can. Take the first afternoon slowly, walk the Small Lake in the cool of the morning, sail out to the monastery with no plan for the rest of the day, and let the island do what it has done for nine centuries — nothing much, very beautifully.

Pine-covered slopes and still water in Mljet National Park.

“Two salt lakes, one small monastery, and a silence so complete you can hear the pines breathing.”

Photo credits

• Parc National Mljet Croatie - Lacs sales: Patrick Rouzet, CC BY-SA 3.0 via Wikimedia Commons
• Sveta Marija Mljet: dronepicr, CC BY 2.0 via Wikimedia Commons
• St. Mary Island in Mljet National Park in Croatia 48612608293: dronepicr, CC BY 2.0 via Wikimedia Commons
• The Mljet National Park in Croatia 48608834026: dronepicr, CC BY 2.0 via Wikimedia Commons
• Otok Mljet u proljeću: August Dominus, CC BY-SA 4.0 via Wikimedia Commons
• Nacionalni park Mljet rano ujutro: August Dominus, CC BY-SA 4.0 via Wikimedia Commons
• Nacionalni park Mljet 9: Andvladimir, CC BY-SA 4.0 via Wikimedia Commons