October the 29th, 2025 – One of the deepest karst springs on Earth is actually located in Lika, but few have ever heard of the stunning lake it is located in…
As Putni kofer writes, if you happen to take the old road from Karlovac down to the Adriatic Sea, the one that passes by the stunning Plitvice Lakes, you will pass by a turnoff that most simply bypass. Bypassing it could be a mistake, because in this part of Lika, away from the most popular tourist routes, there are some wonderful and truly untouched natural attractions.
Turn off a little before Plitvice (if you’re going from the direction of Karlovac) towards Saborsko and Plaški and discover the unspoiled, beautiful and still somewhat wild nature of Lika. You’ll come across the intriguing Lake Sinjac, almost untouched by man, and one of the deepest karst springs on Earth.
one of the deepest karst springs on earth is in lika, yet few visit it…
Lake Sinjac is located near Plaški, and despite having such an impressive claim to fame, few know of it. Embraced on all sides by dense forest, its beautiful turquoise water hides incredible information and mystical stories that have spanned the centuries. This isn’t a lake that beckons you to jump in, but it is ideal for hiking around, relaxing and exploring nature that is rarely visited by human feet. Lake Sinjac is located in a rich karst area, and it is precisely its karst character is its greatest special feature.
Sinjac is a lake that consists of several connected units, while also actually being the source of the Tuk River. At its end, a small river forms, but after only two kilometres, it sinks down underground. There are no visible tributaries, meaning that it is filled only with groundwater, which is rather typical of karst areas. Its surface area is only 0.25 hectares, and the four lakes it consists of are simply called Sinjac 1, 2, 3 and 4.
When the water level is low, all the lakes can be clearly distinguished individually, while when the water level is higher, everything becomes one lake. The deepest is Sinjac 1, and it was the subject of international research that revealed some fascinating data, according to URPI Mala Kapela.
While local people have tried to determine the depth of the lake multiple times throughout the 20th century, due to a lack of equipment, they only descended to a depth of about 40 metres back in the 1980s and to about 100 metres in the late 1990s. When cavers and divers got involved, intrigued by the unusual characteristics of this somewhat bizarre lake, a dive to an incredible 203 metres was achieved on the first lake.
its depths remain unknown to this day
They still didn’t manage to actually reach the bottom, so its final depth is still not known. This data is even more fascinating if we add that Lake Sinjac is currently the third most deeply explored karst spring in Croatia and is among the 15 deepest karst springs in the entire world.
The water in this lake is exceptionally clean, and its colour varies from turquoise-blue to emerald-green, depending on the time of day and lighting conditions. The lake is surrounded by lush greenery and karst rocks, which gives it a special charm and peace. Although not large, the lake has ecological significance because it is home to various plant and animal species that are adapted perfectly to the specific conditions of karst ecosystems.
Due to its inaccessibility and somewhat hidden location, this body of water has remained untouched by mass tourism for centuries, which has further preserved its natural character.
the home of a legend… which ended up being fact
There is also a legend associated with this lake, which turned out to be true! For a long time, the locals of Plaški and surrounding villages told the story of a cart and oxen that ended up in the lake and were never seen again. For a long time, it was thought that this was just a story that was intended to deter children from swimming in the lake and increase their level of caution.
In the end, underwater research really did discover a wooden cart pulled by oxen which lay below the surface! The cart fell into the lake in 1936, got stuck at a depth of 42 metres and remained hidden for decades. To this day, it has not been pulled out of the lake, likely serving as a stark reminder to all those who might want to dive in.
Lika is overlooked in so many ways, and wrongly so. Lake Sinjac is unknown to many, despite being one of the deepest karst springs on Earth and being located in Lika, Croatia’s green heart. This lake may not be enough to be an independent destination in its own right, but its incredible beauty, mysticism and untouched nature certainly deserve a visit during your next trip to Lika.
