Sasyk Lagoon, lagoon in Odesa Region, Ukraine

Sasyk Lagoon is a large coastal water body along the Black Sea in Odesa Oblast. The basin is separated from the sea by a narrow sandy barrier and contains both freshwater and saltwater sections depending on the area.

Until 1978 Sasyk was a two-part lagoon: a fresher northern basin fed by the Kohylnyk and Sarata rivers and a saltier southern part, linked to the Black Sea by a narrow channel through a sand spit up to 0.5 km wide. That year, as the first stage of the Danube-Dniester irrigation system, the spit was widened and reinforced with concrete, and the lagoon was joined to the Danube by a sluiced canal with discharge gates. Repeated flushing with Danube water was meant to leach salt from the bottom mud.

A road runs along the 13,740-metre earthen dam on the sandbar, linking the Katranka resort with the resort area near Prymorske. The dam is 5 metres wide at the top. On the sea side of the sandbar there are sandy beaches where motorists camp informally in summer. The lagoon freezes from December to March.

The lagoon's name comes from a Turkic word meaning "stinking", likely referring to its former salt-marsh smell. Until the 1970s its therapeutic muds made it a resort; after the 1978 dam and Danube canal, the resorts closed and local doctors now advise against swimming. The 13,740-metre earthen dam carries a road linking the Katranka resort with the Primorskoye area.