The coastline stretches across three distinct sections, all oriented in a general north-eastern direction. The first section, from Zatoka Point to Odesa Gulf (Yuzhnyi Cape), is 83 km long; the second, covering Odessa Bay from Cape Yuzhnyi to Cape Severny, spans 16 km; and the third, extending from Cape Severny to Koblevo Point, measures 45 km. In total, the landfill coastline is 144 km long, while the PS4 polygon covers an area of 9,870 km². The sea border itself stretches for 480 km.

Over the last decade, surface water temperatures have ranged from 2°C in winter to 22°C in summer, peaking at 30°C in recent years. Three estuaries—Dnistrovskyi, Sukhyi, and Ajalyk—are connected to the PS4 water area, with the northern and eastern regions influenced by the runoff from the Dnieper-Southern Boug rivers. Occasionally, wind-driven phenomena bring Danube River waters into the area, creating hydrological frontal zones. Salinity ranges from 4 to 19 PSU, and water circulation is cyclonic, primarily influenced by wind patterns, with average current velocity in the upper layer between 5-6 cm/s.

Human activities in the PS4 area, including uncontrolled wastewater discharge, agricultural runoff, and marine litter, have led to eutrophication and water quality deterioration. Military operations contribute further environmental damage, with toxic contamination from explosives, sunken vessels, and destruction of infrastructure like the Kakhovka Dam. Maritime activities, such as port operations, shipping, coastal construction, and tourism, have caused marine pollution and habitat destruction. Overfishing and offshore gas and oil extraction have depleted marine resources, while war-related hazards like military debris, acoustic pollution, oil spills, and barriers like the Kerch Bridge disrupt marine species migration.