Between 11am and 1pm on a sunny calm day, the strongest rays of the sun passing through an underwater opening illuminate the cave with a luminous blue light while objects beneath the surface shimmer in silver and pink. The effect is eerie and unearthly especially if you're lucky enough to see it when the cave is uncrowded which it certainly won't be if you come in July and August.

In fact, the Blue Cave has become a victim of serious overcrowding in the summer. The words "tourist trap" spring to mind on summer days when thousands of visitors wait in lines of up to three hours to spend about five minutes in the cave. I recommend against visiting in high season at all but if you must come, make sure to get there as early as possible and definitely no later than 10am. The cave will be less radiant but still beautiful and much calmer. 

Biševo island is one of the remotest Croatian islands,  located about 4.5 nautical miles from Komiža, the town and the port on the southern shores of Vis island, and the island is very small – it covers the area of just under 6 square kilometres, with a population of just 12 permanent inhabitants. Conveniently connected with daily ferry boat line with Komiža.

How to visit: 

I must warn you that you will encounter big lines, have to pay 10 euros to enter and then you can stay for like 5 minutes. Is it worth it? You decide. But, if you have a boat, you cannot take your own boat there. You have to go in a private boat. Or take a tour with more people!! You can also visit another beautiful similar cave nearby but less wel known, the Medvidova Spilja.

For tours check this link:

https://www.viator.com/searchResults/all?text=blue%20cave%20of%20bisevo&destId=

Happy journeys in Croatia!