Tuzla is a municipality and district of Istanbul Province, Turkey. It has a population of 288,878 (2022) and a land area of 138 km2. It is on the Asian side of the city next to the municipality of Pendik. Tuzla is on a headland on the coast of Marmara Sea, at the eastern limit of the city. The mayor is Eren Ali Bingöl (CHP).

Pendik is a municipality and district of Istanbul Province, Turkey. Its area is 190 km2, and its population is 750,435 (2022). It is on the Asian side between Kartal and Tuzla, on the Marmara Sea. It also neighbours Sultanbeyli, Sancaktepe and Çekmeköy from northwest, Şile from north and Gebze from northeast. The district is home to the Sabiha Gökçen International Airport.