| Kaki Thalassa | |
| Name Local: | Κακή Θάλασσα |
| Periph: | Attica |
| Periphunit: | East Attica |
| Municipality: | Lavreotiki |
| Municunit: | Keratea |
| Population: | 165 |
| Population As Of: | 2021 |
| Elevation: | 23 |
| Coordinates: | 37.8386°N 24.0483°W |
| Caption Skyline: | A beach on the sea the town is named for |
Kaki Thalassa (Greek, Modern (1453-);: Κακή Θάλασσα) is a Mediterranean port town located in the municipality of Lavreotiki, East Attica, Greece, 30 km southeast of the nation's capital, Athens. Kaki Thalassa is 23m (75feet) above sea level. A rural town, it had a total population of 165 according to the 2021 Greek census.
Prior to the 2011 Kallikratis local government reform program, Kaki Thalassa was part of the municipality of Keratea.[1]
The town's name, literally translated, means evil sea, from Greek, Modern (1453-);: [[:wikt:κακή#Greek|κακή]] (the nominative singular form of Greek, Modern (1453-);: [[:wikt:κακός#Greek|κακός]]), meaning bad or evil, and the (feminine gendered) noun Greek, Modern (1453-);: [[:wikt:θάλασσα#Greek|θάλασσα]], meaning sea.