04Open seaLuštica peninsula
The Blue Cave. Swim into the light.
A sea cave on the open-sea side of Luštica, where sunlight comes up through the water and turns it electric blue. The boat waits at the entrance — the last few strokes are yours.
Why it glows
Carved by the sea, lit from below.
On the wild, open-sea side of the Luštica peninsula, the waves have hollowed a single great chamber out of the limestone cliff — about 300 m², with two openings to the sea.
Its colour is a trick of the light. Sunlight slips in beneath the arch, strikes the pale sand a few metres down and rises back through the water — which swallows the warm colours and keeps the blue. From inside, the whole sea seems lit from below: the sunnier the day, the brighter the cave.
It’s the swim our guests talk about long after the trip: cool rock overhead, water that seems to glow beneath you, and nothing but the open Adriatic outside.
- Sunlight strikes the sea outside the cave
- It slips in beneath the arch
- It bounces off pale sand, 3–5 m down
- Only the blue comes back up
- The boat waits outside — you swim in
- one great chamber in the cliff
- ≈ 300m²
- of clear water inside
- 3–5m
- openings to the open sea
- 2
- when the blue is at its brightest
- 10–15h
Getting there
From Tivat, out to the open sea.
Every trip starts on the Tivat promenade. The course crosses the bay to the Kumbor Strait, follows the Luštica shore out past Mamula and rounds Cape Arza, where the bay gives way to the open Adriatic.
- TivatDeparture from the promenade 0 km
- Kumbor StraitInto the outer bay 8 km
- Submarine tunnelThe boat slips into an old navy tunnel 9 km
- MamulaIsland fortress from 1853 17 km
- Fort ArzaBuilt with Mamula to guard the bay 18 km
- Blue CaveSwim in the glowing blue water ≈ 22 km
Map data © OpenStreetMap contributors
Tours that go there
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3 hprivate
BookOpen sea & swimming
Blue Cave Tour
Into an old submarine tunnel, past the island fortress of Mamula and out to the Blue Cave, where the water glows electric blue — swim right in — and on to two more sea caves nearby.
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4 hprivate
BookBay & open sea
Boka Bay + Blue Cave
The bay’s greatest hits in one unhurried loop: the submarine tunnel and Mamula, a swim in the Blue Cave, then back into the bay to Our Lady of the Rocks and Perast.
Prefer your own route? Add the Blue Cave to a Custom Tour of five to eight hours.
On the spot
Swim, float and look up.
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Swim in beneath the arch
The boat stops at the entrance; from there it’s a short swim in. Inside, the water lights up beneath you — dive down and watch your hands turn blue.
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Float and look up
Lie back in the calm water and watch the light from the sea ripple across the rock above you.
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Two more sea caves
The same cliffs hide two smaller, half-open caves, and the tour stops at them too — often with nobody else around.
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Stop at Žanjice
A long pebble beach a few minutes away — a swim stop on the way back, or a lazy hour ashore on a Custom Tour.
- Best light
- The cave glows brightest when the sun is high, roughly from 10:00 to 15:00. In July and August that’s also its busiest time — ask Boris about setting off early.
- Swimming
- Under the new rules, motor boats may not enter the cave, so the boat waits outside and you swim the last stretch. Not a confident swimmer? There are life jackets on board — and the view from the deck is lovely too.
- Sea & weather
- The cave faces the open sea, so it all depends on the waves. If the sea isn’t calm enough, Boris will suggest another time or a sheltered route inside the bay.
- Entrance
- No tickets, no fees — the cave is free to swim in. Only the sea decides when.
- Bring along
- Swimwear and sunscreen (towels are on board) — plus a mask or goggles if you have them: the glow is even better underwater. A waterproof pouch keeps your phone safe for photos.
Keep exploring
On the way out to sea.
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Mamula
Island fortress from 1853
A round fortress on a tiny island at the mouth of the bay, built in 1853 by the Austrian general Lazar Mamula. You pass it on the way to the Blue Cave.
≈ 17 km from Tivat
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Luštica
Hidden coves and clear water
A green peninsula of olive groves and quiet coves between the bay and the open sea. On a Custom Tour, Boris will find you a cove for a long swim.
≈ 18 km from Tivat
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Herceg Novi
Old town and fortresses
The town at the entrance to the bay, founded in 1382 by the Bosnian king Tvrtko I — fortresses, stone stairways and an old town that faces the sea.
≈ 14 km from Tivat
