Kartal is a municipality and district of Istanbul Province, Turkey. Its area is 38 km2, and its population is 483,418 (2022). It is located on the Asian side of the city, on the coast of the Marmara Sea between Maltepe and Pendik.
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. Home to Sabiha Gökçen International Airport. It also neighbours Sultanbeyli, Sancaktepe and Çekmeköy from northwest, Şile from north and Gebze from northeast.
The M4, officially referred to as the M4 Kadıköy - Sabiha Gökçen Airport metro line, is a 33.5-kilometre (20.8 mi), 23-station rapid transit line of the Istanbul Metro. It is colored deep pink on the maps and route signs. Running between Kadıköy and Sabiha Gökçen Airport, it is the first rapid transit line operating on the Asian side of Istanbul. The M4 mostly runs under State road D100, parallel to the Istanbul-Ankara railway and is entirely underground.
Pendik is an underground station on the M4 line of the Istanbul Metro. Located under the Pendik interchange on the D.100 in the Bahçelievler neighborhood of Pendik, Istanbul, it was opened on 10 October 2016 along with the 5 km (3.1 mi) expansion from Kartal to Pendik. It is the closest station to the Turkish State Railways' Pendik station, located 1 km (0.62 mi) south. IETT offers bus service to bridge the gap.
Acıbadem is an underground station on the M4 line of the Istanbul Metro in the Acıbadem neighborhood of Kadıköy, Istanbul. Situated under the D.100 state highway, near Acıbadem Avenue. The station was opened on 17 August 2012 along with the Kadıköy-Kartal portion of the M4 line.
Tavşantepe is an underground station of the M4 line of the Istanbul Metro. Located under beneath the D.100 state highway in the Doğu neighborhood of Pendik, Istanbul, it was opened on 10 October 2016 along with the 5 km (3.1 mi) expansion from Kartal to Pendik.
Ünalan is an underground station on the M4 line of the Istanbul Metro. Located beneath the Uzunçayır Interchange in the Hasanpaşa neighborhood of Kadıköy, Istanbul, it was opened on 17 August 2012 along with the. Connection to the Istanbul Metrobus is available from Ünalan.
Göztepe is an underground station on the M4 line of the Istanbul Metro. Located under beneath the Göztepe Interchange in the Merdivenköy neighborhood of Kadıköy, Istanbul, it was opened on 17 August 2012.
Yenisahra is an underground station on the M4 line of the Istanbul Metro. Located under beneath the D.100 state highway, just west of the Kozyatağı Interchange in the Sahrayı Cedit neighborhood of Kadıköy, Istanbul, it was opened on 17 August 2012. Connections to Havabüs express bus service to Sabiha Gökçen Airport are available.
Kozyatağı is an underground transfer station for the M4 line and the M8 line of the Istanbul Metro. Located under beneath the D.100 state highway in Kozyatağı, it was opened on 17 August 2012 for the M4 and on 6 January 2023 for the M8 line.
Bostancı is an underground station on the M4 line of the Istanbul Metro. Located under beneath the Bostancı Interchange in the Bostancı neighborhood of Kadıköy, Istanbul, it was opened on 17 August 2012. Bostancı is the largest metro station on the M4, consisting of three tracks and two platforms. Connections to IETT bus service is available on both levels of the interchange.
Küçükyalı is an underground station on the M4 line of the Istanbul Metro in Maltepe. It is located beneath the D.100 State Highway, in the Çınar neighborhood. Connection to IETT city buses and Istanbul Minibus service is available. The station consists of an island platform with two tracks and was opened on 17 August 2012.
Maltepe is an underground station on the M4 line of the Istanbul Metro in Maltepe. It is located beneath the Maltepe Interchange, on the D.100 State Highway, in the Zümrütevler neighborhood. Connection to IETT city buses and Istanbul Minibus service is available. The station consists of an island platform with two tracks and was opened on 17 August 2012.
Huzurevi is an underground station on the M4 line of the Istanbul Metro in Maltepe. It is located beneath the D.100 State Highway, in the Bağlarbaşı neighborhood. Connection to IETT city buses and Istanbul Minibus service is available. The station consists of an island platform with two tracks and was opened on 17 August 2012.
Gülsuyu is an underground station on the M4 line of the Istanbul Metro in Maltepe. It is located beneath the D.100 State Highway, just east of the Gülsuyu interchange, in the Cevizi neighborhood. Connection to IETT city buses and Istanbul Minibus service is available. The station consists of an island platform with two tracks and was opened on 17 August 2012.
Esenkent is an underground station on the M4 line of the Istanbul Metro in Maltepe. It is located beneath the D.100 State Highway, just west of the Cevizli interchange, in the Esenkent neighborhood and is the easternmost metro station in Maltepe. Connection to IETT city buses and Istanbul Minibus service is available. The station consists of an island platform with two tracks and was opened on 17 August 2012.
Hastane - Adliye is an underground station on the M4 line of the Istanbul Metro in Kartal. It is located beneath the D.100 State Highway in the Esenkent neighborhood and is the westernmost metro station in Kartal. Connection to IETT city buses and Istanbul Minibus service is available. The station consists of an island platform with two tracks and was opened on 17 August 2012. It is located next to the Anatolian Palace of Justice.
Soğanlık is an underground station on the M4 line of the Istanbul Metro in Kartal. It is located beneath the D.100 State Highway in the Soğanlık Yeni neighborhood. Connection to IETT city buses and Istanbul Minibus service is available. The station consists of an island platform with two tracks and was opened on 17 August 2012.
Yakacık - Adnan Kahveci is an underground station on the M4 line of the Istanbul Metro in Kartal. It is located beneath the D.100 State Highway in the Hürriyet neighborhood and is the easternmost station in Kartal. Connection to IETT city buses and Istanbul Minibus service is available. The station consists of an island platform with two tracks and was opened on 10 October 2016.
The M10 is a rapid transit line in the Asian part of the Istanbul Metro system that leads to Sabiha Gökçen Airport. Initially named and tendered as the M10 Pendik Merkez–Fevzi Çakmak, the line was supposed to complete the link between Pendik railway station and the M4ᴀ extension branch of the M4 line. The tender of this project was later cancelled on 3 January 2018 and on 30 September 2022, a contract was signed with the new contractor company, with a value of ₺2.896.691.000 and works restarted on November 2022.
M4 
İETT Bus: [1] 16C, 16KH, 16S, 16Z, 17K, 17P, 21K, 130, 130A, 130E, 130Ş, 131K, 131V, 131Y, 132C, 132ÇK, 132G, 132M, 132N, 132S, 132T, 132Y, 132Z, 134, 134CK, 134GK, 134K, 134UK, 251, 500T, E-10, KM11, KM12, KM21, KM23, KM25, KM29, KM31, KM32, KM60, KM70, KM71
