The Blue Cave — Plava špilja — is the single most booked boat trip in Montenegro, and the one most people get slightly wrong. It is not in the Bay of Kotor. It sits on the open-sea side of the Luštica peninsula, past the mouth of the bay, and how long you spend getting there depends almost entirely on which town you leave from. This guide covers where it actually is, what the trip involves from each departure point, when the water turns the colour you came for, and how to avoid the two hours of queueing that catch out most July visitors.
What the Blue Cave actually is
It is a sea cave cut into the limestone cliffs of the outer Luštica coast, with two entrances and a chamber you enter by boat. The name comes from what the light does inside. Sunlight passes through the water at the entrance, reflects off a pale sandy patch on the cave floor — unusual on this otherwise rocky coast — and bounces back up, so the whole chamber and everything floating in it glows an intense blue.
The effect is entirely dependent on the sun. On an overcast day the cave is a pleasant grotto and not much more. On a clear day between roughly 11am and 3pm, when the sun is high enough to drive light through the entrance, it is genuinely startling. This single fact should drive your booking: a cheap trip on a grey morning is worse value than a pricier one at midday in good weather.
Where it is, and why that matters for your booking
The cave lies near the tip of the Luštica peninsula, close to Žanjice and Mirišta beaches and the fortress island of Mamula. That puts it a long way from Kotor and very close to Herceg Novi — a distinction most tour listings gloss over.
From Herceg Novi — the short trip
Roughly 20–30 minutes each way by boat. Herceg Novi sits at the mouth of the bay, so you are already most of the way there. Boats leave from the town waterfront and the marina all through the season. This is the cheapest and fastest way to do it, it leaves your day largely intact, and it is the option to choose if the cave is the main thing you want to see. See our Herceg Novi guide for the town itself.
From Kotor — the long trip
Roughly 50–70 minutes each way, covering 12–15 nautical miles down the length of the bay and out through the Verige strait into open water. Speedboats run at 25–35 knots and the ride out is genuinely enjoyable — you pass Perast, the islands and the whole length of the fjord. But understand what you are buying: on a Kotor departure, most of the day is the journey, not the cave.
That is not a reason to avoid it. Kotor tours almost always run as a circuit taking in Our Lady of the Rocks at Perast, the abandoned Yugoslav navy submarine tunnels cut into the cliffs, Mamula island and a swimming stop, with the cave as one stop among several. Judged as a full-day bay cruise it is good value. Judged as a way to see one cave, it is a long way round.
From Tivat, Budva and the rest of the coast
Tivat departures sit between the two in length. Budva and points south involve a substantial open-sea run and are usually sold as full-day excursions; if you are staying on the Budva riviera it is often faster to drive to Herceg Novi and take a boat from there than to sail the whole way.
What a typical tour includes
Beyond the cave itself, the standard circuit from the bay covers some combination of:
- Our Lady of the Rocks — the man-made islet off Perast, usually with time ashore to see the church.
- The submarine tunnels — tunnels driven into the cliffs on the Luštica side to hide Yugoslav navy vessels. Boats go inside.
- Mamula island — the circular Austro-Hungarian fortress at the bay mouth, used as a prison camp during the Second World War and since converted into a hotel. Most tours circle it rather than land.
- Žanjice or Mirišta — a swimming and lunch stop on one of the better beaches on this coast.
- Rose — the small village opposite Herceg Novi, sometimes included for lunch. See our Rose guide.
Check before booking whether swimming inside the cave is included. Many boats stop outside and let you swim in; some enter and let you jump from the boat. In peak season, some do neither because of the queue behind them.
When to go
Time of day: late morning to early afternoon, on a sunny day. Outside that window the blue is muted.
Time of year: the season runs roughly May to October. July and August bring the warmest water and the worst crowding — upwards of fifty boats a day work the cave, and at midday you may wait your turn to enter. Late May, June, September and early October give you much the same weather with a fraction of the traffic, which is the single best piece of advice on this page.
Sea state: this is open Adriatic, not sheltered bay. When the wind is up, tours are cancelled or the cave becomes inaccessible even if the boat sails. Operators generally reschedule or refund, but build a spare day into your plans rather than leaving it to your last afternoon.
Practical notes
- Book the early slot. The first departures of the day reach the cave before the queue builds, and the light is usually good enough by late morning.
- Small boat or big boat. Small speedboats enter the cave and move faster; larger catamarans are more comfortable and cheaper per head but often stop outside. Ask which yours does.
- Bring water shoes. The entry points on this coast are rock, not sand.
- Take cash. Beach and boat operators on the Luštica side are not reliably set up for cards.
- Sun cover. There is no shade on an open boat, and the reflected glare off the water is stronger than it feels.
Is it worth it?
Yes, with a caveat. Go from Herceg Novi on a clear day in June or September, in the middle of the day, on a boat that goes inside, and it is one of the best two hours you will spend on this coast. Go from Kotor in the second week of August, in cloud, on a boat that queues outside and turns around, and you will wonder what the fuss was about.
The cave is a real natural attraction that has been slightly overwhelmed by its own popularity. Almost everything that determines whether you enjoy it is decided when you book, not when you arrive.
