| Postsee | |
| Location: | Kreis Plön, Schleswig-Holstein |
| Pushpin Map: | Schleswig-Holstein |
| Coords: | 54.2306°N 10.2408°W |
| Inflow: | Alte Schwentine, Nettelau, Honigau, Neuwührener Au |
| Outflow: | Schwentine |
| Basin Countries: | Germany |
| Length: | 4.8km (03miles) |
| Width: | 1.2km (00.7miles) |
| Area: | 276.4ha |
| Depth: | 3.9m (12.8feet) |
| Max-Depth: | 9.1m (29.9feet) |
| Shore: | 11.1km (06.9miles) |
| Elevation: | 20.6m (67.6feet) |
| Cities: | Preetz |
Postsee is a lake in Kreis Plön, Schleswig-Holstein, Germany. At an elevation of 20.6 m, its surface area is 276.4 ha.