Blue Cave
Coastal Region
The Blue Cave, locally known as Modra špilja, is a stunning flooded sea cave located on the east side of Biševo island in the Croatian Adriatic. Renowned for its mesmerizing glowing blue light, the cave's unique illumination occurs when sunlight enters through a submerged entrance on the southern side. This natural phenomenon creates an iridescent aquamarine glow throughout the grotto, with underwater objects appearing silver. The cave is approximately 24 meters long, 10 to 12 meters deep, and up to 15 meters high, formed by the erosive wave action on limestone rock. Originally accessible only by diving, an artificial entrance was constructed in 1884 to allow small boats to enter. The Blue Cave is a popular tourist destination, attracting over 10,000 visitors annually, often combined with visits to the nearby Green Grotto, which features a similar emerald-green light effect. Its natural beauty and unique lighting phenomenon make it one of the most iconic natural attractions in the Adriatic region.
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Tip: The best time to visit the Blue Cave is between 11 AM and 12 noon when the sunlight creates the most vivid aquamarine glow inside the cave. Visitors should consider purchasing tickets in advance during peak tourist seasons to avoid long waits. Small boats are used to enter the cave through the artificial entrance, so be prepared for a potentially narrow and low passage. Combining the visit with a trip to the nearby Green Grotto is recommended for a fuller experience of Biševo's natural wonders. Discounts may be available for groups, children, or seniors, so inquire locally.
Interesting facts
- •The Blue Cave's glowing blue light is caused by sunlight entering through a submerged southern entrance and reflecting off the white cave floor.
- •The cave measures approximately 24 meters in length, 10-12 meters in depth, and up to 15 meters in height.
- •An artificial entrance was created in 1884 to allow small boats to enter, inspired by Baron Eugen von Ransonet's exploration.
- •The Blue Cave attracts over 10,000 visitors annually and is often paired with visits to the nearby Green Grotto, which glows emerald green.
- •The cave's natural entrance resembles a vaulted ceiling, a unique geological feature.
History
The Blue Cave was first described and painted by Baron Eugen von Ransonet in the 19th century.
Initially, the cave was accessible only by diving due to its natural underwater entrance.
Following his suggestion, an artificial entrance was built in 1884 to allow small boats to enter safely.
Over the years, the cave has become a renowned natural attraction, drawing thousands of visitors annually.
Its formation is attributed to the erosive action of the sea waves on the limestone composing Biševo island.
Place Guide
Artificial Entrance1884
Constructed in 1884 to allow small boats to enter the cave safely, replacing the original underwater-only access.
Natural Underwater Entrance
A submarine-like opening on the cave's southern side through which sunlight enters, creating the iconic blue glow.
Interior of the Blue Cave
A flooded limestone cave illuminated by sunlight reflected from the white cave floor, bathing the interior in aquamarine light and making underwater objects appear silver.
