Medvidina Cave Biševo – Monk Seal and 160 Meters of Underground

Medvidina Cave on the island of Biševo is one of the most impressive marine caves in the Croatian Adriatic. It is hidden in the Trešjavac Cove on the southern side of the island, far from the busiest routes to the Blue Cave, and its large dark opening in the steep rocky coast indicates that it is a completely different place.

The cave is approximately 160 meters long, with its entrance rising about 27 meters above sea level. From a large open foyer, it gradually becomes narrower, lower, and darker, until it ends deep inside with small gravel beaches.

This hidden final part is the reason for its name.

Medvidina Cave was once a habitat for the Mediterranean monk seal, one of the most endangered marine mammals in the world. On Vis and Biševo, it was known as “morski covik”, and the peaceful beach deep within the cave provided a safe place for resting and raising young.

Today, monk seals no longer use the cave, but its natural value remains so significant that the entire site is under special protection.

Where is Medvidina Cave located?

Medvidina Cave is located on the southern coast of Biševo, in Trešjavac Cove.

Unlike the Blue Cave on the eastern side of the island, there is no organized land access to Medvidina. The steep coast practically prevents normal pedestrian access to the entrance.

Access is exclusively by sea.

The simplest starting point is Komiža, from where smaller excursion or private boats can reach the southern side of Biševo.

Medvidina Cave is often included in coastal tours of Biševo, but visiting it does not operate like a tour of the Blue Cave. There is no classic ticket office, queue of small boats, or a few minutes of organized navigation through illuminated interiors.

This is a much more natural, sensitive, and demanding location.

Huge entrance approximately 27 meters high

The most impressive moment comes before entering the cave.

A large fissure approximately 27 meters high and about 7 meters wide opens in the vertical rock of Biševo. The geopark describes it as a large stone door formed by a fault in the rock.

From the sea, the entrance appears as a dark crack between two massive stone slabs.

Unlike the Blue Cave, where a boat passes through a very low opening, here in the first part of the cave, a massive stone vault rises above.

Only deeper inside does the space begin to narrow significantly.

The cave is about 160 meters long

From the large entrance, Medvidina Cave extends approximately 160 meters deep into Biševo.

Initially, the space is large and sufficiently illuminated by daylight entering through the opening.

As one goes deeper, the cave becomes narrower and lower, and natural light diminishes.

After a while, one enters a zone of almost complete darkness. The sea continues between the rocks, and at the very end, there is a small gravel beach.

This arrangement – a large marine entrance, a long dark corridor, and a small dry beach at the end – created an almost ideal shelter for the Mediterranean monk seal.

Why is it called Medvidina Cave?

The name comes from the Mediterranean monk seal (Monachus monachus).

This is the only species of seal that naturally lives in the Mediterranean Sea and one of the rarest marine mammals in the world.

On Vis, it was traditionally called morski čovik or morski covik.

The seal seeks hard-to-reach marine caves with hidden beaches inside for resting and breeding. Medvidina Cave is just such a place.

The animal could swim deep under the rock, emerge on a small beach, and remain hidden from waves, people, and views from the open sea.

For this reason, this cave is not only a geological phenomenon but also one of the historically most important habitats for the Mediterranean monk seal on the eastern coast of the Adriatic.

The last confirmed monk seal on Biševo

The Mediterranean monk seal is no longer considered a permanent resident of Biševo.

The Viški Archipelago Geopark states that the last monk seal recorded on Biševo was in 1964, when it was killed by fishermen. Subsequent genetic research showed that it was an adult female.

This is a rather sad detail in the island's history, but it clearly shows how much the attitude towards nature conservation has changed since then.

Today, a potential return of the monk seal to the area of Vis and Biševo would be an extremely important event.

Populations of this species still exist in other parts of the Mediterranean, particularly in the Aegean Sea, so the possibility of occasional appearances in the Adriatic cannot be completely ruled out.

For this reason, Medvidina Cave is protected as a potential future habitat for the species.

The small beach at the end of the cave is not a tourist bathing area

One of the most interesting aspects of Medvidina Cave is the small gravel beach at its end.

However, it is important to understand its function.

This is not a hidden beach that tourists are recommended to swim to and leave a towel.

The beach has historically been a place where the Mediterranean monk seal would come ashore and raise its young, so today it is part of a particularly sensitive habitat.

According to visiting rules, one must not go to the beach at the end of the cave.

This is one of those cases where it is better to see less and preserve more.

Can you enter Medvidina Cave by boat?

It is very important to distinguish between approaching the cave by boat and entering its interior with a motorboat.

Access to the entrance is normally possible by vessel.

However, motor vessels are prohibited from entering the interior of Medvidina Cave.

The reason is not only the possibility of hitting the rocks.

In the deep part of the cave, air exchange is very poor, so exhaust gases from the engine linger inside. A large number of vessels have also caused physical contact with the rocks and damage to protected geological structures over the years.

For this reason, it is now appropriate to approach the cave by boat, but motor vessels should remain outside its interior.

Can you swim in the cave?

Yes, swimming and diving are generally not prohibited, but only with respect for protection rules and actual sea conditions.

This is an important distinction compared to entering with a motor vessel.

The relevant authorities assess that swimming and diving with responsible behavior can have a significantly lower impact on the cave.

However, this does not mean that it is an ordinary bathing area.

Deep inside the cave, there is no natural light, the space narrows, the water can be colder, and the distance from the exit becomes significant.

For this reason, entering deeper into the cave is not something that an insecure swimmer or someone without experience in marine caves should attempt.

Do not use lighting without permission

The protection rules of Medvidina Cave are stricter than one might expect.

Inside, lighting devices may not be used without permission, unnecessary noise must not be created, nor should animals be disturbed.

The reason is the very sensitive ecosystem of darkness.

Species that live deeper in the cave are adapted to almost complete absence of light, so strong and frequent illumination changes the conditions of their habitat.

This means that the cave is not a place for group exploration with strong spotlights for photography.

The cave is full of life despite appearing completely dark

At first glance, the interior of Medvidina Cave looks like a dark stone tunnel.

In fact, it is a very rich marine habitat.

Research conducted in 2019 recorded 123 species of marine organisms.

In the first, still illuminated part of the cave, large schools of fish can regularly be seen.

Deeper in the darkness, small crustaceans appear, while the rocks are inhabited by sponges, moss animals, polychaetes, and other species adapted to life in marine caves.

Among the recorded animals are strictly protected species, such as the red starfish and the dentex.

For this reason, Medvidina Cave is not just an empty geological space, but a true underwater ecosystem hidden within Biševo.

Protected since 1967

Medvidina Cave has been protected as a geomorphological monument of nature since 1967.

Today, it is also included in the European ecological network Natura 2000 as part of a valuable habitat type of submerged and partially submerged marine caves.

It is also located within the UNESCO Global Geopark Viški Archipelago.

Protection was not introduced only because of its appearance.

The value of the cave consists of its geology, great length, specific underwater marine habitat, and historical importance for the Mediterranean monk seal.

How to visit Medvidina Cave from Komiža?

The most practical starting point is Komiža.

Biševo is located just southwest of Vis, and local boatmen are well acquainted with its coast and conditions around Medvidina Cave.

If the cave is the main goal, one should look for an excursion that explicitly includes the southern side of Biševo and Medvidina Cave. It should not be assumed that every standard trip to the Blue Cave will automatically visit it.

The Blue Cave is on the other side of the island and has a completely organized tour system, while Medvidina is a more natural and sensitive location.

It is best to go with a local skipper who knows the rules and can assess the sea conditions at the entrance.

Sea conditions are crucial

Medvidina Cave is located on the open southern side of Biševo, exposed to the sea and waves.

For this reason, it is not enough for the day to be sunny.

If there is swell, entering the water in front of the large stone opening can become uncomfortable or unsafe, and waves crashing against the rocks create additional risks.

A local skipper can assess the conditions much better than a visitor seeing the cove for the first time.

If the sea is not good, there is no reason to force entry.

Medvidina will be there next time.

Be cautious of the rocks above the entrance

The rock around the entrance is naturally very fragmented and eroded.

In the past, there have been reports of rockfall, which is why the relevant authorities have warned visitors to exercise caution.

Therefore, one should not linger directly under the steep rocks unnecessarily or attempt to climb the edges of the cave.

Medvidina is a natural site, not a developed tourist attraction with nets, fences, and organized walkways.

This is part of its appeal, but it requires more responsible behavior.

Medvidina or Blue Cave?

These two caves are located on the same small island, but almost nothing else is the same.

The Blue Cave is known for its intense blue light, small entrance, and short organized tour by an official boat.

Medvidina Cave is much longer, darker, and more natural. The entrance is huge, the interior extends about 160 meters into the rock, and the biggest story is not a play of light but geology, complete darkness, and the former habitat of the Mediterranean monk seal.

The Blue Cave is a visual spectacle.

Medvidina offers much more of a wild marine cave experience.

If there is enough time on Biševo and the sea is suitable, it is worth seeing both precisely because they are so different.

Can it be connected with other Biševo attractions?

Yes, but Medvidina is best connected with the boat tour of the southern coast of the island due to its location.

Above the cave area runs the Geostaza Biševo, and near Cape Gatula, there are old positions of the coastal artillery battery.

From the organized battery, there is a view towards Medvidina Cave and the islet Kamik, so the cave can also be seen from a completely different perspective during a walking tour of the island.

This is a good combination for a visitor who does not want to explore Biševo only from the sea.

One day can combine the Blue Cave, the interior of the island, and Geostaza, while Medvidina is visited by boat when sea conditions are good.

Is Medvidina Cave suitable for children?

The view of the cave from the boat can be excellent for children, but swimming entry is not equally suitable for all ages.

One must consider the open sea, deep water, steep rocks, and dark interior without organized safety features.

For small children, it is sufficient to approach the entrance by boat and see the large opening from the outside.

Older children who swim very well can consider potential entry only under appropriate supervision, calm seas, and adherence to all current rules.

This is not a place to prove swimming abilities.

Best time to visit

There is no "magic hour" for Medvidina Cave like there is for the Blue Cave.

Here, the most important factor is calm seas.

A sunny day provides a nicer color of the water in front of the entrance and a stronger contrast between the illuminated sea and the dark interior, but safe conditions are more important than the position of the sun.

Summer offers the highest probability of stable weather, but even then, sea conditions can change rapidly.

Morning tours are often more pleasant due to lower temperatures and less boat traffic.

A place to see, but also to leave untouched

Medvidina Cave is one of those attractions where more visitors does not necessarily mean better tourism.

It was once calm enough that the Mediterranean monk seal raised its young deep inside.

Today, that peace is no longer the same, and significant tourist pressure has already left traces on the protected site.

Therefore, the right way to visit is not to try to go as deep as possible, illuminate every corner, and photograph the small beach at the end.

It is much more valuable to approach the large opening from the sea, respecting current rules, possibly swim in the allowed area, and experience how daylight behind gradually turns into almost complete darkness.

In this lies the greatest difference between Medvidina and the Blue Cave.

The Blue Cave dazzles with light. Medvidina impresses due to darkness, size, and the feeling of entering deep into the wild part of Biševo.

Location: Trešjavac Cove, southern coast of Biševo
English name: Monk Seal Cave
Type: semi-submerged marine cave
Length: about 160 m
Height of entrance: about 27 m
Width of large fault entrance: approximately 7 m
End of the cave: small gravel beach
Special feature: former habitat of the Mediterranean monk seal – “morski covik”
Protection: geomorphological monument of nature since 1967
Natura 2000: yes
UNESCO: part of the UNESCO Global Geopark Viški Archipelago
Land access: no classic access to the entrance
Arrival: exclusively by sea, most practically from Komiža
Motor vessels in the interior: prohibited
Swimming and diving: allowed with respect for current protection rules and safety conditions
Beach at the end of the cave: not allowed to visit
Lighting in the cave: not allowed without permission
Best for: nature lovers, marine caves, geology, and exploring Biševo