Nikaia (, NÃÂkaia), known before 1940 as Kokkinia (, Kokkiniá), is a town and a suburb of the Piraeus agglomeration, in the southwestern part of the Athens urban area, Greece. Since the 2011 local government reform it is part of the municipality Nikaia-Agios Ioannis Rentis in the regional unit of Piraeus, and it is the seat and a municipal unit of the municipality.
Nikaia is located north of Piraeus, and west of central Athens. The municipal unit has an area of 6.649 km<sup>2</sup>. The main streets are Gregori Lambraki Street and Petrou Ralli Street.
According to the station of the National Observatory of Athens Nikaia has a hot semi-arid climate (Köppen climate classification: BSh) with mild winters and hot summers.
Nikaia metro station of line 3 is situated in the city. There are also many buses servicing the city (OSY).
On August 17, 1944 the Executions of Kokkinia took place. It was the largest Nazi roundup and one of the largest-scale war crimes committed during the German occupation of Greece.
Nikaia, like many other places around Greece, owes its population eruption to Greek refugees who were forced out of Asia Minor after the 1919-1922 Greco-Turkish war ended. It was part of the municipality of Piraeus until 1933, when it became a separate municipality, then still under the name Nea Kokkinia. It was renamed to Nikaia in 1940.
The 8th International Tournament of Nikaia, a chess tournament, took place between August 19 and 27, 2000. The Greek Weightlifting Grand Prix took place in Nikaia on December 9 and 10, 2003.
Nikaia has four sport clubs with important history. These are Proodeftiki with a great successful history in the football, Ionikos Nikaias with successful departments in the football (Ionikos Nikaias F.C.) and basketball (Ionikos Nikaias B.C.), A.E. Nikaias, and Aris Nikaias.