The Blue Cave on Luštica, the «sapphire of Boka»

Of all the stops boats make around the mouth of the Bay of Kotor, the Blue Cave gets the most photos. It’s a sea cave on the Luštica peninsula, near Herceg Novi, known locally as Plava špilja. The National Tourism Organisation calls it the «sapphire of Boka», and while brochure nicknames usually oversell things, this one makes sense the moment your boat slides in and the water lights up.

Why is the water so blue?

The printed «Life on Luštica» map, a joint effort by Tivat and Herceg Novi, explains it simply. Sunlight comes in through the mouth of the cave and reflects off the walls, turning the water a crystal blue you can see with the naked eye, and better still with a mask on. The National Tourism Organisation adds that there are large boulders inside that look as if they’ve been painted blue. The same leaflet ranks it among the largest and most beautiful caves on the Adriatic, which I can’t verify with measurements, as no official source publishes any.

Finding it

It’s on the Luštica shore between Zlatna luka inlet and Cape Mokra gora, and OpenStreetMap places it in Herceg Novi municipality. There’s no path. You come by sea, and the most direct way is on the summer boats from Škver harbour in Herceg Novi, which run to Mirište, Žanjic and the cave itself. Lots of boat trips round the bay from Kotor, Tivat and Budva include it too; the official tourist board runs the boat season from May to November and admits prices vary with the boat, the group size and the route. I couldn’t find an official fare, so compare a few before booking.

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Swimming inside

The part worth paying for is getting in the water. The leaflet gives a depth of up to 5 m, fine for snorkelling and easy swimming, and the tourist board positively encourages a dip. My rule is simple. If the trip on offer just nudges its bow in and backs out again, it isn’t the one I’d book.

One warning. Gov.uk points out that in summer speedboats and jet skis sometimes come too close to swimmers, and at the mouth of a cave with boats coming and going that matters. Stay within sight of your skipper, and if anything goes wrong at sea, the rescue number is 129.

Fitting it into your day

The neatest plan pairs it with a beach. The National Tourism Organisation suggests exactly that from Žanjic, a few minutes away, or from the fishing village of Rose. If you want more, the island fortress of Mamula, at the entrance to the bay, is another regular stop on these trips. I’d go first thing, before the mid-morning boats bunch up, and keep the afternoon for the beach.

If you are staying the night, see the best hotel deals in Herceg Novi for your dates: the well-placed rooms go fast.