Blue Cave (Modra ŠPlija)

Blue Cave (Modra Špilja) is an underwater cave located on Biševo island, near Vis island in Croatia, known for the shimmering blue light that fills its interior. The cave can be entered either underwater or by boat through a narrow corridor that broadens into a large space sitting partly below and partly above the sea surface. Depths at the site range from 3 to 40 metres, and the site is rated suitable for beginners through to advanced divers. Beyond the cave itself, diving toward the neighbouring cove offers additional terrain to explore, including wall diving.

The defining experience here is the vivid blue optical effect created when light refracts through the submerged entrance and illuminates the cave interior. This effect is at its strongest during the summer months, specifically in the afternoon when the angle of sunlight is most favourable. The cave holds a wealth of fish species, along with algae, snails, and sea urchins.

Access is by boat, with entry possible either through the underwater passage or via the narrow surface corridor. The site sits within reach of Vis island as a day-trip destination.