Blue Cave Montenegro: Boat Tours from Kotor & Herceg Novi

The Blue Cave (Plava Spilja) is a sea grotto on the open-Adriatic side of the Lustica peninsula that glows an electric blue when the sun hits it, and the only way in is by boat. Where you set off from decides your whole day: Herceg Novi is the shortest run to the cave, Kotor and Perast pair it with the bay and Our Lady of the Rocks, and Tivat or Budva turn it into a longer coastal cruise. Group tours run from roughly €30 to €45 per person, the season is April to November, and the blue is strongest in the middle of the day. Here is how to pick the right boat and see the cave at its best.

What the Blue Cave actually is

It is a cave cut into the limestone cliffs where the Lustica peninsula meets the open sea, just west of the entrance to the Bay of Kotor and about six nautical miles from Herceg Novi. The colour is the whole point. Sunlight enters through an opening below the waterline, bounces off the pale sea floor and floods the cavity with a glowing blue light, so the water looks lit from underneath rather than from the sky. Boats nose in through a low mouth, and on most trips the engine cuts and you get ten to thirty minutes to jump in and swim in that blue water.

A few physical facts shape the visit. The water near the cave is fairly shallow, around 5 m, and unusually clear - locals claim 20 m of visibility outside the mouth - so you can watch fish over the pale bottom while you swim. In summer the sea sits at a swimmable 20-22°C, and boats carry a small ladder to get you back aboard. There is no entry fee: the cave is open water, and everything you pay goes to the boat, not the cave.

One honesty note that catches people out: not every operator lets you swim inside. Some treat the cave as look-don’t-touch to protect it and let you swim only at the mouth, while others take the boat right in and let you dive off. If the swim is the reason you are going, ask before you book rather than assume - it is the single most common disappointment on these trips.

Which port should you leave from?

This is the decision that matters most, because the cave sits far to the west and the run there eats into your day. Four coastal towns run tours, and they are not interchangeable.

Herceg Novi is the closest base and the one to pick if the cave is your priority. It sits at the mouth of the bay, so boats reach Lustica in roughly 40-50 minutes and you spend more time in the water and less in transit. Trips here tend to be half-day, three to five hours, and often the best value. For the town itself, its old town and beaches, see our Herceg Novi guide.

Kotor and Perast sit deep inside the bay, so the boat has to run all the way out and back - a longer day, but you get the whole bay as a bonus and most tours from here loop in Our Lady of the Rocks, the man-made island church off Perast. If you would rather have one trip that combines the bay’s headline sights with the cave, this is it; our full Bay of Kotor boat tour guide covers that itinerary, the church and its museum in detail.

Tivat (Porto Montenegro) falls between the two - a mid-length cruise that takes in the marina and the inner bay on the way. Budva is the farthest and offers the fewest sailings, so a Blue Cave trip from there is a long day on the water; it makes sense only if Budva is your base and you do not mind the transit.

Prices and what you get

Be wary of exact prices - they move with the season, the operator and whether you go group or private, so treat every number as a starting point and confirm before you pay. As a rough guide, group speedboat tours start around €30 per person from Herceg Novi and closer to €45 from Kotor, the difference being the longer run from inside the bay. A private boat, often for up to a dozen people, costs more but lets you set the timing - worth splitting between a family or a group who want the cave at 09:00 before the crowds.

As a real benchmark, the Herceg Novi operator Petar Boats lists a Blue Cave trip - the cave, Mamula and the Rose submarine tunnel - at €30 per adult, €15 per child aged 6-11 and free under six, leaving from Igalo and Herceg Novi. Use it to sanity-check what you are quoted, and always ask what is included: some prices cover the fuel and the guide only, while a swim stop, drinks or snorkel gear may cost extra.

Best time of day, and the season

Timing changes the whole experience, and most people get it slightly wrong. The blue is at its strongest when the sun is high, roughly 10:00 to 13:00 - go too early and the light is weak, go mid-afternoon in July and you join a queue of boats waiting to squeeze through the same low mouth. The sweet spot is a mid-morning departure: enough sun for the colour, ahead of the lunchtime crush. Book the earliest slot you can bear and you may get the cave nearly to yourself.

The season runs roughly April to November, with daily sailings through the summer and the widest choice in July and August - which is also the busiest and hottest window. Late spring and September give you warm water and calmer seas without the peak-season scrum; for how the coastal months compare, see our best time to visit Montenegro guide. Whatever month you pick, bring sunscreen, a hat, a towel and a light layer, because a speedboat at pace throws real wind-chill even in August.

What else the trip usually stops at

A Blue Cave outing is rarely just the cave - the run out passes a cluster of quick, odd stops, and a well-run three-hour speedboat can string several together. Mamula is a round Austrian fort on its own islet at the mouth of the bay, built in the 1850s, used as a prison and internment camp in the Second World War, and now a luxury hotel; most boats circle it for the photo. The Rose submarine tunnel is a Cold-War bolt-hole cut into the rock where the Yugoslav navy hid submarines - boats slip into the dark mouth, and it is the kind of thing you would never find alone. Zanjice, a long pebble beach on Lustica, is the usual spot for a second, calmer swim before the run home.

For the wider geography of the peninsula the cave sits on - its beaches, villages and how it is developing - see our Lustica peninsula guide, and for how the coast links up by road and water, getting around Montenegro.

Is it worth it, and who should skip it?

For most people with a spare morning on the coast, yes. The colour is genuinely strange, the swim is the memorable bit, and the cave is unreachable any other way, so the boat is the attraction as much as the transport. The honest caveats: if you are prone to seasickness, the open-sea leg past the bay mouth can be choppy in an afternoon wind, so go early and sit low and central. If you cannot swim or would rather not, you will still see the blue from the boat, but half the point is getting in the water. And if a dozen other boats are already queued at the mouth when you arrive, the magic thins fast - which loops back to the one rule that matters here: go mid-morning, and go early in the day before the crowds build.

Nearby / read also

• Bay of Kotor boat tour - the fuller bay itinerary, with Our Lady of the Rocks.
• Herceg Novi travel guide - the closest base for the cave.
• Lustica peninsula
• Getting around Montenegro
• Best time to visit Montenegro
• Things to do in Montenegro - the country-level shortlist the cave belongs to.