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View from the rim down into a karst sinkhole near Imotski, with iron-stained cliffs dropping to a small disc of dark water far below.
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NatureDalmatian hinterland

Imotski's Blue and Red Lakes: Two Sinkholes, One Detour Inland

Two collapsed cave systems on the edge of a small Dalmatian town — one of them the deepest lake-bearing sinkhole in Europe, the other occasionally a football pitch.

Dalmatian hinterland, Croatia

Two Holes in the Karst

The Imotski lakes are not lakes in any normal sense. They are collapsed cave systems — Dinaric karst at its most theatrical — formed when the roofs of enormous underground halls gave way several million years ago. What is left at the surface is a pair of near-vertical sinkholes punched into the limestone plateau, with water that rises and falls on the schedule of the rock rather than the sky.

The two sit only about a kilometre apart on the western edge of Imotski town and now anchor the Biokovo-Imotski Lakes UNESCO Global Geopark, established to protect the wider plateau between the Adriatic coast and the Herzegovinian border. You can see both in a single morning.

Whether that morning is worth driving inland for depends entirely on what you came to Croatia to look at. The geology rewards a detour; it does not reward crossing the country.

Quick Facts

Where

Imotski, on the eastern edge of Split-Dalmatia County, roughly 100 km from Split and 15 km from the Bosnia-Herzegovina border.

Getting there

About 1 hour 10 minutes by car from Split via the A1; FlixBus and Globtour run several daily services from Split bus station (around 1 hour 45 minutes, roughly €10–15).

Red Lake (Crveno jezero)

Cliffs of 241 m above water and a total explored depth of around 530 m — the deepest collapse doline with a lake on the planet.

Blue Lake (Modro jezero)

A 220 m drop from rim to floor, with a walking path down to the water when conditions allow.

Best time

Late April to early June, when Blue Lake is full and walkable on the rim trail without summer heat.

Cost

Both lakes are free to visit; parking near the Blue Lake viewpoint is informal and unmetered.

Crveno jezero

Red Lake: A View, Not a Walk

Crveno jezero is the more extreme of the two, and the one most people end up looking at for fewer minutes than they expected. The pit drops 241 m of sheer cliff above the water and continues for hundreds of metres below it, with a total explored depth of around 530 m and an estimated volume of 25–30 million cubic metres. That makes it the third-largest sinkhole in the world by volume, and the deepest known collapse doline that still contains a lake.

You cannot descend to the water. The cliffs are unclimbable for casual visitors, and most exploration has been done by technical cave divers reaching the lake floor via narrow underground passages. What you get from the visitor side is a fenced viewing platform on the rim, the reddish iron-oxide stain that gives the sinkhole its name, and the strange flatness of the water 240 m below your boots.

Most people stay about ten minutes. That is not a criticism — it is simply what the place offers, and ten minutes spent staring straight down into a 530 m hole is more memorable than an hour at most coastal viewpoints.

Close framing of the reddish-orange limestone walls of a collapse doline plunging vertically to a still pool of dark blue water.
Modro jezero

Blue Lake: The Path Down, and the Years It Disappears

Modro jezero is the lake you actually visit. A switchback path, partly cut into the rock and partly built up with stone, drops from the rim near the town footpath down to the water — roughly 200 m of vertical descent in well-graded zigzags, taking 20 to 30 minutes down and a little more back up. In a full year, the lake fills the bottom of the sinkhole as a deep blue-green disc, fed by snowmelt from the surrounding mountains; in spring it has historically reached 90 m of water depth, and in 1914 it crested at 114 m and spilled over the southern rim.

In dry years, it vanishes. The lake bed has been bare or close to it in recent dry summers, including conditions confirmed as late as November 2025, and what you find at the bottom is then a flat field of pale limestone and cracked silt rather than water. This produces the other thing Imotski is quietly famous for: a football match played on the dry lake floor between two local sides nicknamed the Vilenjaci (Elves) and the Vukodlaci (Werewolves). The first game was played in 1943 and only a handful have happened since, the most recent in 2011, ending 2:2. It is essentially impossible to time a visit to coincide with one. Knowing it happens is part of why the place feels different from a standard viewpoint.

If you want to swim, plan for late spring or early summer in a wetter year — locals do swim here when the level is high — and ask in town before walking down, because conditions change quickly and the path can be closed after rain.

Aerial view of a turquoise karst lake set in a bowl of pale limestone, ringed by pine and oak — the visual signature of Dalmatian hinterland water-filled sinkholes.
Imotski Town

The Town, the Fortress, and the Karst Plateau Around It

Imotski itself is small, slow, and worth an hour or two on top of the lakes rather than a destination in its own right. The Topana fortress, built in the 10th century on the cliffs directly above Blue Lake, is now an open viewpoint and a venue for occasional summer events; the walk up from the town centre takes about fifteen minutes and gives you the best single view of the lake and the surrounding plateau. The Baroque Church of Our Lady of Angels sits just below the fortress and is the source of the name Gospin dolac — "Our Lady's vale."

The vale in question is the next sinkhole over, and the local football club, NK Imotski, built their stadium inside it. Stadion Gospin dolac took thirteen years to construct between 1976 and 1989, holds around 4,000 people on stone terraces cut into the karst, and was named one of the ten most beautiful stadiums in the world by the BBC in 2017. You can see it from the fortress wall without paying for anything. If there is a match on while you are in town — NK Imotski plays in the Croatian second tier — it is one of the more unusual football experiences in Europe.

Two food things are worth knowing about. Imotska torta is a dense almond and citrus tart made with shortcrust pastry, prošek, maraschino, and a long list of spices, traditionally baked for weddings and saint's days and protected as an Original Croatian product; several patisseries in town sell it by the slice. Rafioli, smaller almond pastries from the same tradition, are easier to take with you. Neither is a reason to make the drive on its own, but both are better than what you will eat at a coastal restaurant aimed at tourists.

View from the Biokovo massif looking out across the coast — the limestone range that frames the Imotski plateau on its seaward side.
Practical Info

How to Fit It Into a Trip

The honest framing: Imotski works best as a half-day detour, not a destination. If you are already based around Split, Makarska, or anywhere on the central Dalmatian coast, the drive takes about an hour each way and you can be at both rims, down to the Blue Lake water, up to the fortress, and back in your car by mid-afternoon. If your only Croatian time is on the islands, skip it.

By car

Take the A1 from Split toward Ploče and leave at the Šestanovac exit, then a regional road across the plateau to Imotski — about 1 hour 10 minutes for roughly 90 km. Parking near the Blue Lake viewpoint is informal but reliable; the Red Lake car park is signed from the same road five minutes further on. A hire car turns this into a flexible half-day.

By bus

FlixBus and Globtour run several daily services from Split bus station to Imotski, taking about 1 hour 45 minutes for €10–15. The Imotski station is a 15-minute walk from the Blue Lake viewpoint and another five from Red Lake. Without a car you are committed to walking between the two lakes and the fortress, which is fine in spring and autumn but punishing in midsummer heat.

What to combine it with

On the same day from a coastal base you can pair the lakes with the Biokovo Skywalk above Makarska and the Biokovo coastal road, all of which use the same A1–Šestanovac axis. From an inland trip toward Mostar or the Cetina valley, Imotski sits naturally on the route. Trying to pair it with the islands rarely works — give it up and use the day for something coastal instead.

What to bring

Sturdy trainers for the Blue Lake descent — the switchbacks are stone and gravel, not technical but unforgiving after rain. Water, especially in summer; there is shade on the way down and almost none on the way back up. A wide-brim hat for the Red Lake viewing platform, which has no cover at all.

FAQ

Frequently Asked Questions

Yes, when the water level is high enough — typically late spring and early summer in a normal year — and locals do swim here. In drier years the lake can shrink dramatically or vanish entirely, so check current conditions in town before walking down with a swimsuit. There are no lifeguards, no facilities, and the water is cold.

Plan for two to three hours on foot: ten minutes at the Red Lake viewpoint, an hour to ninety minutes for the round trip down to Blue Lake and back, and another twenty minutes for the walk up to Topana fortress. Add lunch in town and you have a comfortable half-day.

It is steep but not technical — well-built switchbacks of stone and gravel, no exposure, no scrambling. Sturdy trainers are fine in dry weather; the surface gets slippery after rain. The climb back up is the hard part, particularly in summer heat, so go early or in shoulder season.

The name comes from the cliffs, not the water. The surrounding limestone walls are stained reddish-brown by iron oxides, and at certain angles in afternoon light the whole pit takes on that colour. The water itself reads as dark blue or near-black from the rim, given the depth.

For a half day, yes — particularly if you have a car and a base anywhere between Split and Makarska. For a longer trip, only if you are already heading inland toward Mostar, the Cetina valley, or the Imotski plateau itself. They are geologically extraordinary but visually compact; they will not occupy a full day.

Only when Blue Lake dries out completely, which happens irregularly. The exhibition match between the Elves and the Werewolves has been played a handful of times since 1943, most recently in 2011. The pitch is not a permanent fixture, the surface is whatever the lake bed has dried to, and you cannot reliably plan a visit around it.

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