The deep sea bay was formed by the rise of the sea level in the post-glacial period. In the past it was a karst sinkhole which probably contained freshwater at one time (between 10,000 and 6,000 years from now), it was later filled by the sea through karst fissures and the narrow passage to the open sea through the Soline Channel.
- Surface: 145 hectares
- Coastline length: 9240 m
- Maximum depth: 47 m
- Temperature: December: min 10.6 °C (at the bottom); August: min 11.6 °C (below 25 m), max: 15.2 °C (middle layer); max: above 25 °C (surface layer).
- Salinity: December: min 37.5 ‰ (surface up to 10 m); August: min 38.4 ‰ (from 10 to 15 m); max: 37 ‰ (from 17-20m)
The Great Lake merges with the open sea through a long and wide canal at a place called Veliki most (Great Bridge), and from that point it spreads into the Soline Channel and then meets the open sea. Up to 1958 Veliki most was shallower and narrower than today, which resulted in the creation of strong currents which changes direction every six hours depending on the tides. Veliki most was demolished in 1958 and it has been reconstructed in 2016.
- Surface: 24 hectares
- Coastline length: 2600 m
- Maximum depth: 29 m
The Small Lake is part of the lake system most indented into the land. It is connected to the Great Lake by a shallow and narrow canal. The seawater alternates through it under the influence of tides. A stone bridge is built above the canal, known as Mali most (Small Bridge). Small boats can pass through the narrow canal. The shores of Small Lake are very rugged and richly covered with thick pine tree tops which stretch to the sea.