Odysseus Cave

Odysseus Cave (Odisejeva špilja) is one of the most atmospheric hidden gems on the Croatian island of Mljet, tucked into the southern coastline near the village of Babino Polje. A collapsed section of limestone roof reveals a rounded, egg-shaped chamber filled with seawater that glows an almost unreal turquoise — a sight that draws travelers looking for something quieter than the Adriatic's headline attractions.

Where does the name come from?

According to local legend, this is the very spot where the shipwrecked Homeric hero Odysseus washed ashore and was kept — part guest, part captive — by the nymph Calypso, ruler of the island. He is said to have stayed seven years before the gods allowed him to sail home. Islanders point to details in the "Odyssey," where olive trees and vineyards grow right next to the wreck site, as matching Mljet's own landscape, which explains why locals believe their island is the mythical Ogygia. A rival version of the same legend is sometimes claimed by Malta, but Mljet's own tradition around the cave has been passed down for generations regardless.

How do you get there?

The easiest approach is on foot from the center of Babino Polje: a clearly marked trail leads to the cave entrance in roughly 20 minutes. The path isn't technically demanding, but sturdy shoes help for the final rocky stretch down toward the water. Visitors arriving by boat, whether from elsewhere on Mljet or from nearby Korčula, can also reach the cave from the sea — the opening is about 4-5 meters wide, wide enough for a small boat or a confident swimmer to pass through.

What will you actually see inside?

The interior's main draw is light. Sunlight pouring through the collapsed opening bounces off the water's surface and paints the chamber walls and seabed in a shifting blue glow. The effect peaks around midday in summer, when the sun sits high enough to shine almost straight down into the cave. The water itself is remarkably clear, which makes the spot popular with snorkelers and free divers — though it's worth remembering this is a wild, natural pool with no beach infrastructure, changing rooms, or lifeguards.

When should you visit?

June through September gives the best combination of calm seas and strong midday sun needed for the cave's signature lighting. Outside that window, swell can make the sea entrance genuinely risky, and rough weather can close off access entirely. Aim for late morning or midday to catch the light at its best and to beat the small crowds that build up around the main trailhead in peak season.

Practical tips for planning

Because the cave sits close to Mljet National Park, many visitors combine the walk with a visit to the park's saltwater lakes and the monastery on St. Mary's Islet. Getting to Mljet itself means taking a ferry, most commonly from Dubrovnik, Split, or Korčula, so it's worth building the crossing into a full-day itinerary rather than treating the cave as a standalone stop.

Frequently asked questions

Can I reach the cave on foot? Yes — a marked trail runs from Babino Polje to the cave entrance, taking about 20 minutes each way.

Do I need to swim to see the inside? To get into the water-filled chamber itself, yes: the only way in is through the narrow sea entrance, either swimming or by small boat. On foot, you can only reach the rocky edge above the opening.

What's the best time of day to visit? Midday during summer, when the sun shines nearly straight down through the collapsed roof and produces the strongest blue light effect.

Is the Odysseus legend historically accurate? No — it's a local tradition inspired by Homer's "Odyssey" rather than a documented historical fact. Islanders on Mljet believe their island corresponds to Calypso's mythical Ogygia.