Blue Grotto

The Blue Cave (Modra špilja) is a sea cave on the eastern side of Biševo island, roughly 5 km southwest of Komiža on Vis. The cave owes its fame to a striking light phenomenon: sunlight enters through an underwater opening, bounces off the pale seabed, and floods the interior with an intense blue glow. Its discovery was made public in 1884, and it has since become one of the most recognisable natural attractions among the Croatian islands.

How do you get there?

The starting point is Komiža on the island of Vis. From there, a speedboat or fast boat takes about 15 minutes to reach Mezuporat bay on Biševo. On arrival, visitors switch to a smaller wooden boat, since the cave's entrance is narrow and low, too tight for larger vessels. There are two ways to do this: join an organised excursion (often combined with a wider island-hopping tour), or make your own way there on a public boat from Komiža and then line up on-site to buy a ticket for the small boats going inside.

What will you actually see inside?

The interior itself is a small, intimate chamber where the main attraction is the light rather than the rock formations. Sunbeams pass through an underwater opening, reflect off the white, sandy floor, and turn the water and cave walls an intense, almost fluorescent blue. The effect shifts with the angle of the sun and tends to be strongest around midday. The visit itself is brief, typically just a few minutes, since boats need to make way for the next group waiting outside.

When is the best time to visit?

The most reliable months are June through August, when the weather is settled and the sea calm. That said, this is also peak tourist season, so expect queues and crowds at the cave entrance. Aim for the morning or midday hours, when sunlight hits the underwater opening at the best angle and produces the strongest glow. The whole visit is weather-dependent: if the sea is rough, boats may be barred from entering the cave for safety reasons.

What does it cost, and how should you prepare?

Entry to the cave itself usually runs from about €12 to €24 per person, depending on the season, paid in cash on-site unless it's already bundled into an organised tour. On top of that comes the transport cost: a one-way ticket on the public boat from Komiža runs around €4 in high season, slightly less outside it. It's worth allowing extra time, since queues can get long during peak season, and operators reserve the right to cancel trips if sea conditions turn unfavourable.

Frequently asked questions

Can you visit the Blue Cave without an organised tour? Yes. You can take the public boat from Komiža to Mezuporat bay, then buy a ticket on-site and join the queue for the small boats that enter the cave.

How long does the whole trip take? The crossing from Komiža takes about 15 minutes, and the boat ride inside the cave lasts just a few minutes. Counting queues and waiting time, the full outing usually takes anywhere from 1.5 hours to a few hours.

When is the blue light effect strongest? It's most intense on sunny days around midday, when sunlight hits the underwater opening at the right angle to light up the cave.

What happens if the sea is rough? In choppy conditions, the cave entrance can be closed off for safety, and boat trips may be cancelled or rescheduled — worth factoring in if you're planning a visit outside the calmest summer weeks.