The real reason why this top European travel destination has such blue water

Croatia's Adriatic Sea is renowned for its crystal-clear waters and stunning blue hues. Therefore, it comes as little surprise that tourists from all over the world have been flocking to this stunning European destination for many years.

In fact, in 2024, the Balkan country saw over 21.3 million tourist arrivals and more than 108.7 million overnight stays, an impressive increase compared to the previous year. However, few visitors understand why Croatia's stunning coastline and islands boast such a breathtaking body of water. The reason lies in several different factors, which combine to produce a landscape hard to find anywhere else on Earth.

The Adriatic Sea is fed by several rivers, including the Po—the longest river in Italy—and Croatia's Neretva—the largest in the eastern part of the Adriatic basin. These rivers carry sediment and nutrients that contribute to the water's colour and clarity.

However, Croatia's unique sea colour and clarity are also influenced by its geographic location and connection to Africa.

The waters of the Adriatic are, of course, connected and influenced by the Mediterranean Sea, which in turn is connected to the Atlantic Ocean via the Strait of Gibraltar.

The Mediterranean, and therefore the Adriatic, is known for its deep blue colour, which is caused by the high concentration of salt in the water. The water is also influenced by the winds and currents that come from Africa.

Winds and currents that come from the north of the African continent travel upwards through the Mediterranean, carrying warm water and nutrients towards the Adriatic. These stimulate the growth of phytoplankton, which require sunlight to grow.

The clear waters of the Adriatic Sea allow plenty of sunlight to penetrate, promoting the growth of microscopic organisms. As they grow and multiply, they release oxygen and absorb carbon dioxide, which helps to maintain the water’s clarity.

Croatia’s sea is not only clear and blue—it is also the cleanest in Europe. According to a 2024 report by the European Commission and the European Environment Agency, which examined the waters of all 27 EU countries as well as Albania and Switzerland, Croatia has the most places to swim with excellent-quality water.

More than 99% of the beaches monitored across Croatia were judged to have excellent sea quality for swimming. Greece took second place, followed by Cyprus and then Austria.