Buna Spring

Overview

The Buna spring (Vrelo Bune) is one of the most powerful karst springs in Europe — the emergence point where an underground river pours out from a cave at the base of a 200-metre limestone cliff, in the village of Blagaj, 12 km southeast of Mostar. Average discharge is 43 cubic metres per second; during heavy spring runoff, peaks exceed 100 m³/s. The water is intensely cold (10°C year-round), exceptionally clear, and drinkable at the source.

Why this spring: Herzegovina sits on one of the world's most extensive karst landscapes — porous limestone that allows water to dissolve and tunnel through rock over millions of years. The Buna is fed by rainfall on the Podveležje plateau, which disappears underground and travels several kilometres through a complex cave system before emerging at Blagaj. The spring system is still being explored by cave divers; passages over 3 km deep have been mapped.

Visual impact: the water exits the cave with enough force to form a visible plume — not a trickle, but a river. Within 100 metres of the source the Buna is already a full-width emerald river, about 15 metres wide and up to 4 metres deep. The contrast between the black cave mouth, the white limestone cliff above, and the turquoise water below is the reason this site is photographed so often.

The Blagaj Tekija connection: the 16th-century Sufi dervish monastery was built here specifically because of the spring — the Bektashi and later Naqshbandi orders chose this site for the spiritual symbolism of pure water emerging from stone. The tekija and the spring are visually inseparable: the monastery is built just above the cave mouth. See our dedicated Blagaj Tekija page for monastery visit information.

The Buna river itself flows just 9 km before joining the Neretva near Mostar — making it one of the shortest rivers in the Balkans. It's famous for its clarity (you can see the bottom in deep pools) and for supporting wild trout (pastrmka), which are the centrepiece of Blagaj riverside restaurants.

Boat rides to the cave: small wooden boats run from the tekija area to the cave mouth and a short distance into the tunnel. Tickets are 15–20 KM (€8–10) per person, duration 15–20 minutes. The boats are flat-bottomed and stable; the tunnel ceiling is low in places (lean back). Operators run April through October; winter is too dangerous due to high water.

For travellers on our tours: the Buna spring is visually inseparable from Blagaj Tekija — our Mostar Full-Day and Sarajevo tours stop for 30 minutes and include the spring view. The boat ride is optional and at your own expense; ask the driver if time allows.

Practical notes: the riverside path is flat and accessible. Swimming in the Buna is legal but bracing (10°C will take your breath); locals occasionally do it in August. No entrance fee to view the spring itself. Parking is in the village lot, 200 metres from the site.

Where is it?

Buna Spring is in Mostar. See our Mostar travel guide for more in the area.