Biševo – Beyond the Blue Cave

A Small Island with a Story Far Bigger Than Its Size

Biševo lies about five kilometres southwest of Vis, across the channel from Komiža. The island covers 5.91 square kilometres, and its highest point, Stražbenica, rises to 239 metres. For many visitors, however, Biševo means one thing: the Blue Cave. Boats arrive at Mezoporat, passengers transfer to the authorised cave boats and, within a few hours, most are on their way back towards Vis.

That is one way to see Biševo, but it leaves most of the island unexplored. Beyond the cave are sandy bays, an interior settlement with an 11th-century church, former vineyards, old paths and a 19-kilometre geotrail crossing a landscape that once supported a much larger permanent community. The 2021 Croatian census recorded 23 inhabitants on Biševo, while local historical sources record around 350 before the Second World War.

More than the Blue Cave

Biševo is largely built of limestone, but parts of the island are covered by deposits of wind-blown sand dating from the Quaternary period. These deposits are particularly important around Salbunara and in parts of the interior, where they have influenced both vegetation and agriculture. Much of the coast is steep and difficult to approach, so everyday movement on and off the island has long depended on a handful of accessible bays.

Three of these are especially important today. Mezoporat, on the eastern side, is the main arrival and transfer point for visits to the Blue Cave. Porat and Salbunara, both on the western side, offer a very different experience, with sandy shores and easier access to the island’s interior. The contrast between the bays helps explain why Biševo feels quite different once you move away from the Blue Cave route.

The Blue Cave itself, Modra špilja, lies in Balun Bay and has been protected as a geomorphological monument of nature since 1951. Its blue light is created when sunlight enters through a submerged opening and reflects from the pale seabed into the cave. Although local fishermen knew the cave long before tourism developed, it became widely known after the Austrian painter and explorer Eugen von Ransonnet visited in 1884 and promoted it beyond the island.

Access is now regulated. Visitors enter in authorised small boats from Mezoporat, and swimming and diving inside the cave are prohibited. Sea conditions determine whether visits can operate, so current information should always be checked rather than assuming the cave will be accessible on a particular day.

Porat, Salbunara and the western coast

Porat is one of the easiest places on Biševo to spend time rather than simply pass through. The sandy beach lies in a sheltered bay on the western coast, with vegetation rising behind it and footpaths connecting the shore with the interior. Nearby Salbunara is smaller and quieter, with sand that forms part of a wider geological feature rather than simply being material deposited along the waterline.

The wind-blown sands around Salbunara support specialised vegetation and are one of the reasons the western side of Biševo differs from much of the rocky coastline elsewhere in the Vis archipelago. They also contributed to the agricultural potential of parts of the island, particularly for vines. Moving between Porat, Salbunara and the inland settlements makes that connection between geology, agriculture and settlement much easier to see than a short boat visit does.

Mezoporat has a more functional role. Its small pebble beach sits beside the transfer point for the Blue Cave, and in summer the bay can be busy with excursion traffic. For anyone planning a longer stay on Biševo, it is useful to think of Mezoporat primarily as a gateway, while Porat and Salbunara provide better starting points for experiencing the island beyond the cave.

Poje and the island’s medieval history

The interior settlement of Poje, often written Polje in standard Croatian, developed around some of Biševo’s more useful agricultural land. Here stands the Church of St Sylvester, the clearest surviving link with the island’s medieval history. According to the Vis Archipelago Geopark, the church was built in 1050 by the Split priest Ivan Gaudijev Grlić and given to Benedictine monks from the Tremiti Islands on the Italian side of the Adriatic, who later established a monastery nearby.

The church was originally pre-Romanesque, although later rebuilding altered its appearance. A 13th-century image known as the Madonna of Biševo was once kept here and is now held in Hvar Cathedral. These connections show that Biševo was part of a wider Adriatic religious and maritime network long before its modern relationship with tourism.

Poje also tells a much more recent story. Biševo’s first school opened in 1921 in a private house in Porat, and in 1937 island residents built a dedicated school building in Poje. It remained in use until 1961, when the number of school-age children had fallen too far for it to continue. The former school, church and surrounding houses are therefore reminders that the island was once home to a considerably larger year-round community.

A population shaped by fishing and farming

Before the Second World War, local historical sources record approximately 350 people living on Biševo. By the 2021 census, the permanent population had fallen to 23. Residents moved to Komiža and other parts of Croatia, while others emigrated much farther, including to the United States and Australia.

The relationship with Komiža remained particularly close throughout these changes. Families moved between the two islands, fishermen worked the surrounding waters and people who relocated to Vis often retained houses, vineyards or other land on Biševo. The island may look isolated on a map, but socially and economically it has long belonged to the maritime world centred on Komiža.

Agriculture formed an important part of that economy. Vines grew particularly well in some of the sandy soils, and Plavac became closely associated with the island. Olives, figs and other crops were also cultivated, usually within a mixed system in which households combined fishing with farming rather than relying entirely on one occupation. Small vineyards remain around Poje, Potok and Salbunara, although scrub and woodland now cover much of the land that was once worked more intensively.

Old fields, stone boundaries and abandoned agricultural plots should therefore not be read simply as picturesque traces of the past. They show how much work was required to maintain a permanent population on an island with limited freshwater, dry summers and no direct road connection to a larger market.

Medvidina špilja and the protected coast

The Blue Cave is not Biševo’s only protected sea cave. Medvidina špilja, the Monk Seal Cave, lies in Trešjavac Bay on the southern coast and extends approximately 160 metres into the rock. Its large entrance gradually narrows towards a small beach deep inside the cave.

The name refers to the Mediterranean monk seal, Monachus monachus, which historically used caves along this coast for shelter and breeding. The species is no longer a regular resident of Biševo, but the cave remains an important protected habitat and geomorphological site.

Visitor behaviour here is now specifically regulated. In June 2026, the Vis Archipelago Geopark and the responsible protected-area authority reiterated that motorised vessels are prohibited from entering the cave interior. The restriction responds to physical damage from boats, exhaust accumulation and wider pressure on the protected environment. Medvidina should therefore not be treated as simply another sea cave to enter whenever conditions appear calm.

Walking across Biševo

Walking changes the scale of Biševo. The island is small, but the distance between its bays, interior settlements and higher ground is enough to reveal landscapes that are invisible from an excursion boat. The Biševo Geotrail extends for about 19 kilometres and links geological sites, beaches, settlements and cultural remains across the island.

Stražbenica, the highest point at 239 metres, can be reached from the Velo Gora area by a marked route of about two kilometres. Parts of the path are steep and narrow, and the open terrain means that summer heat can make a relatively short distance more demanding than expected. Shade is inconsistent, while shops and other services are limited away from the principal bays.

Anyone planning to walk should therefore carry sufficient drinking water, sun protection and suitable footwear, and leave enough time for the return journey. Water deserves particular attention because Biševo does not have its own public drinking-water network. Drinking water is delivered to the island by tanker according to local needs, so conserving it is a practical necessity for residents rather than simply an environmental message aimed at visitors.

Getting from Komiža to Biševo

Komiža is the main departure point for Biševo and the community with which the island has the strongest historical and transport links. State passenger line 612 connects Komiža with Biševo and serves Mezoporat, Salbunara and Porat according to the published timetable. The service operates through the year, but frequency varies considerably by season and sailings remain dependent on weather and sea conditions.

Private excursion boats and water taxis provide additional options, particularly in summer. Anyone planning to spend several hours walking or moving between bays should check the current public-boat timetable shortly before travelling, paying particular attention to the last return to Komiža rather than relying on an old schedule found online.

Weather is part of that planning. Biševo lies directly exposed to the open Adriatic, and conditions can differ considerably from those around Vis Town or even Komiža. A calm morning does not guarantee the same conditions later in the day, while wind direction can make one side of the island much rougher than another. Changes and cancellations are therefore part of travelling to a small offshore island rather than an unusual failure of the service.

A small island under pressure

Biševo forms part of the Vis Archipelago UNESCO Global Geopark, and its surrounding waters are included within the Natura 2000 ecological network. The wider marine environment includes reefs, Posidonia seagrass meadows, coralligenous habitats and numerous submerged or partially submerged caves. Bottlenose dolphins are also present in the waters of the archipelago.

The environmental value of the area sits alongside increasing visitor pressure, especially around the Blue Cave. Biševo has little infrastructure relative to the number of people who can arrive during summer days, so responsible behaviour matters. Visitors should avoid anchoring on Posidonia meadows, respect restrictions at protected caves, take rubbish away, stay clear of private houses and working land and avoid creating informal paths through sensitive vegetation.

The same principle applies to water. On an island where drinking water has to be delivered, unnecessary use has more immediate consequences than it might in a larger destination with extensive infrastructure.

Seeing Biševo as an island, not an excursion

A Blue Cave trip shows one remarkable geological feature. Spending longer on Biševo reveals how much surrounds it: the sandy deposits at Salbunara, the beach at Porat, the church and former school in Poje, surviving vineyards and paths crossing land once worked by a much larger population.

These places also make the relationship with Komiža clearer. For generations, people moved between the two islands to fish, cultivate land, trade and eventually relocate. Biševo is geographically separate from Vis, but its social history is closely tied to the community across the channel.

That is why the island makes more sense when treated as a place in its own right rather than simply as the location of the Blue Cave. The cave is part of Biševo’s story, but the island around it has a history, landscape and community of its own.

Sources & Further Reading

Vis Tourist Board – Biševo / Blue Cave / Porat Official visitor information about Biševo, including the Blue Cave, Porat Bay, access and key places to explore.

Vis Archipelago Geopark – Biševo, geology and Natura 2000 Background on Biševo’s geology, protected landscapes, marine habitats and its role within the Vis Archipelago.

Vis Archipelago Geopark – Medvidina Cave Official information about Medvidina Cave, its natural significance and guidelines for responsible visits.

Visit Croatia – Biševo and the Blue Cave Practical travel information about reaching Biševo, its beaches, caves and connections from Komiža.