The Kaydak Inlet or Sor Kaydak (Russian: Залив Кайдак) is a narrow inlet or arm at the eastern end of the Dead Kultuk (former Komsomolets), a bay of the Caspian Sea in the coast of Kazakhstan.

[1] The inlet was shallow and cut deep into the coast extending east and then roughly southwards in a SSW direction.

[2] In the same manner as the Dead Kultuk, the Kaydak Inlet had a distinct coastline in former times, but in the 1990s and 2000s, with higher Caspian Sea levels, the water penetrated inland through the neck of the bay producing waterlogged marshes.

[3] The water in the shallow inlet had striking colours, in which delicate tones of blue or of brown predominated according to the seasons.

[4] With shrinking Caspian Sea level in the 2020s as a result of global warming and increased evaporation, the Kaydak Inlet became dry.