# List of longest subway tunnel sections

This page presents a list of the longest continuous underground rapid transit tunnel sections of the world, excluding branches from the longest tunnel (branch lines that used to transport passengers should be included).
Note: This article only lists tunnels that are 15 km (6.2 miles) or longer.

## World's longest subway tunnel sections in use

| Name | System | Country | Stations | Length in km (mi) | Year of completion |
| Lines 3-11 | Suzhou Metro | China | Line 3 and Line 11 are connected at Weiting Station with through trains passing by. | 86.54 km (53.77 mi) | 2019–2023 |
| Line 6 | Chengdu Metro | China | Wangcong Temple – Lanjiagou | 68.2 km (42.4 mi) | 2020 |
| Line 3 | Guangzhou Metro | China | Haibang – Airport North | 68.2 km (42.4 mi) | 2005–2024 |
| Line 19 | Chengdu Metro | China | Huangshi to Tianfu | 67 km (42 mi) | 2020–2023 |
| Line 1 | Qingdao Metro | China | Dongguozhuang to Wangjiagang | 59.82 km (37.17 mi) | 2020–2021 |
| Line 18 | Guangzhou Metro | China | Xiancun to Wanqingsha | 58.3 (36.2) | 2021 |
| Bolshaya Koltsevaya line | Moscow Metro | Russia | Circle route | 57.54 km (35.75 mi) (excluding Moscow-City branch) | 2018–2023 |
| Line 10 | Beijing Subway | China | Circle route | 57.1 (35.5) | 2008–2013 |
| Line 7 | Guangzhou Metro | China | Meidi Dadao – Yanshan | 54.24 (33.7) | 2016–2023 |
| Line 6 | Beijing Subway | China | Jin'anqiao – Lucheng | 53.4 (33.2) | 2012–2018 |
| Seoul Subway Line 5 (longest branch) | Seoul Subway | South Korea | Banghwa–Hanam Geomdansan | 51.7 km (32.1 mi) | 1995–2021 |
| M11 | Istanbul Metro | Turkey | Gayrettepe – Arnavutköy Hastane | 51.5 (32) | 2023–2024 |
| Line 2 | Wuhan Metro | China | Julong Boulevard - Fozuling | 50.347 (27.556) | 2012–2019 |
| Line 16 | Beijing Subway | China | Bei'anhe – Wanpingcheng | 48.9 (30.4) | 2016–2023 |
| Sokolnicheskaya line | Moscow Metro | Russia | Potapovo – Bulvar Rokossovskogo | 47 (29) | 1935–2024 |
| Arbatsko-Pokrovskaya line | Moscow Metro | Russia | Pyatnitskoye Shosse – Shchyolkovskaya | 45.1 (28.0) | 1938–2012 |
| Lyublinsko-Dmitrovskaya line | Moscow Metro | Russia | Zyablikovo – Fiztekh | 44.3 (27.5) | 1995–2023 |
| Line 11 | Guangzhou Metro | China | Longtan – Chisha | 43.2 km (26.8 mi) | 2024 |
| Zamoskvoretskaya line | Moscow Metro | Russia | Khovrino – Alma-Atinskaya | 42.8 (26.6) | 1938–2018 |
| Line 8 | Beijing Subway | China | Yuzhi Lu – Wufutang | 42.6 (26.4) | 2012–2021 |
| Line 15 | Shanghai Metro | China | Gucun Park – Zizhu Hi-tech Park | 42.3 (26.3) | 2021 |
| Line 5 | Chengdu Metro | China | Jiudaoyan – Huilong | 42.3 (26.3) | 2019 |
| Tagansko-Krasnopresnenskaya line | Moscow Metro | Russia | Planernaya – Kotelniki | 42.2 (26.2) | 1966–2015 |
| Line 14 | Beijing Subway | China | Dawayao – Shangezhuang | 42 (26) | 2015–2021 |
| Line 6 | Tianjin Metro | China | Nanhezhuang – Lushuidao | 42 (26) | 2016–2021 |
| Downtown MRT line | Mass Rapid Transit (Singapore) | Singapore | Bukit Panjang – Expo | 41.9 (26) | 2013–2017 |
| Line 3 | Nanjing Metro | China | Xinghuolu – Mozhoudonglu | 41.5 (25.8) | 2015 |
| Line 4 | Suzhou Metro | China | Longdaobang — Tongli | 41.5 (25.8) | 2017 |
| Serpukhovsko-Timiryazevskaya line | Moscow Metro | Russia | Altufyevo – Bulvar Dmitriya Donskogo | 41.2 (25.6) | 1983–2002 |
| L-12 (Metro Sur) | Madrid Metro | Spain | Circle route | 40.96 (25.5) | 2003 |
| Toei Oedo Line | Toei Subway | Japan | Hikarigaoka – Shiodome – Tocho-mae | 40.7 (25.3) | 2000 |
| Seoul Subway Line 9 | Seoul Subway | South Korea | Gimpo Airport – VHS Medical Center | 40.6 (25.2) | 2018 |
| Line 12 | Shanghai Metro | China | Qixin Road – Jinhai Road | 40.4 (25.1) | 2015 |
| Line 7 | Beijing Subway | China | Beijing West railway station - Universal Resort | 40.3 (25.0) | 2021 |
| Line 4 | Chengdu Metro | China | Wansheng – Chengdu University | 39.3 (24.4) | 2015–2017 |
| Line 7 | Chengdu Metro | China | Circle route | 38.6 (24.0) | 2017 |
| Kaluzhsko-Rizhskaya line | Moscow Metro | Russia | Medvedkovo – Novoyasenevskaya | 37.8 (23.5) | 1958–1990 |
| Line 1 | Chengdu Metro | China | Weijianian – Science City | 37.47 (23.3) | 2010–2018 |
| Line 2 | Shenzhen Metro | China | Chiwan – Xinxiu | 35.78 (22.23) | 2011 |
| Busan Subway Line 2 | Busan Transportation Corporation | South Korea | Jangsan–Dongwon | 35.5 (22.06) | 1999 |
| Seoul Subway Line 6 | Seoul Subway | South Korea | Eungam Loop – Bonghwasan | 35.1 (21.8) | 2001 |
| Seoul Subway Line 7 (longest branch) | Seoul Subway | South Korea | Cheongdam – Bupyeong-gu Office | 35.1 (21.7) | 2012 |
| Line 5 | Tianjin Metro | China | Beichenkejiyuanbei – Liqizhuangnan | 34.8 (21.6) | 2018–2021 |
| Line 7 | Shanghai Metro | China | Panguang Road – Huamu Road | 34.4 (21.38) | 2010 |
| Line 8 | Guangzhou Metro | China | Wanshengwei—Jiaoxin | 33.9 (21.1) | 2010–2020 |
| M4 | Istanbul Metro | Turkey | Kadıköy – Sabiha Gökçen Havalimanı | 33.5 (20.8) | 2012–2022 |
| Circle MRT line | Mass Rapid Transit (Singapore) | Singapore | Dhoby Ghaut – HarbourFront | 33.3 (20.69) | 2009–2012 |
| L-7 | Madrid Metro | Spain | Hospital del Henares – Pitis | 32.9 (20.5) | 2007 |
| U7 | Berlin U-Bahn | Germany | Rathaus Spandau-Rudow | 31.8 (19.7) | 1924–1984 |
| Line 1 | Beijing Subway | China | Pingguoyuan – Dawang Lu | 31.0 (19.3) | 1971–2000 |
| Solntsevskaya line | Moscow Metro | Russia | Aeroport Vnukovo – Delovoy Tsentr | 30.9 (19.2) | 2014–2023 |
| IND Eighth Avenue Line and IND Fulton Street Line | New York City Subway | United States | Inwood – 207th Street – Grant Avenue | 30.8 (19.14) | 1956 |
| Line 2 Orange | Montreal Metro | Canada | Côte-Vertu – Montmorency | 30.8 (19.14) | 2007 |
| Thomson–East Coast line | Mass Rapid Transit (Singapore) | Singapore | Woodlands North – Gardens by the Bay | 30.4 km (18.9 mi) | 2020–2022 |
| Line 2 | Shanghai Metro | China | East Xujing – Longyang Road | 30.2 (18.77) | 2010 |
| Moskovsko-Petrogradskaya Line | Saint Petersburg Metro | Russia | Parnas–Kupchino | 30.1 (18.7) | 1961–2006 |
| Line 8 | Shanghai Metro | China | Shiguang Road – Luheng Road | 29.7 (18.45) | 2009 |
| Kirovsko-Vyborgskaya Line | Saint Petersburg Metro | Russia | Devyatkino – Prospekt Veteranov | 29.57 (18.4) | 1955–1978 |
| Line 8 | Chengdu Metro | China | (Phase 2 is 7.94 km) | 29.1 (18.1) | 2020 |
| Line 2 | Chengdu Metro | China | Tianhe Road – Chengdu Institute of Public Administration | 29.0 (18.0) | 2012–2013 |
| Bannan Line (Taipei Metro Blue Line) | Taipei Metro | Taiwan | Dingpu – Taipei Nangang Exhibition Center | 28.2 (17.6) | 1999–2015 |
| Line 4 | Beijing Subway | China | Anheqiao Bei (N) – Gongyi Xiqiao | 28.2 (17.5) | 2009–2010 |
| Incheon Subway Line 1 | Incheon Subway | South Korea | Bakchon – International Business District | 27.9 (17.42) | 1999–2009 |
| Line 14 | Paris Métro | France | Saint-Denis–Pleyel – Aéroport d'Orly | 27.8 (17.3) | 1998–2024 |
| Northern line | London Underground | United Kingdom | Morden – East Finchley | 27.8 (17.2) | 1890–1940 |
| Nevsko-Vasileostrovskaya Line | Saint Petersburg Metro | Russia | Begovaya–Rybatskoye | 27.7 (17.2) | 1967–2018 |
| Tanimachi Line | Osaka Metro | Japan | Dainichi–Nagahara | 27.1 (16.7) | 1967–1983 |
| M5 | Istanbul Metro | Turkey | Üsküdar – Samandıra Merkez | 26.5 (12.5) | 2017–2024 |
| Meijo Line | Nagoya Municipal Subway | Japan | Kanayama–Nagoya Dome-mae Yada-Kanayama | 26.4 (16.4) | 1965–2004 |
| B Line | Los Angeles Metro Rail | United States | North Hollywood - Union Station | 26.4 (16.4) | 1993–2000 |
| Frunzensko-Primorskaya Line | Saint Petersburg Metro | Russia | Komendantsky Prospekt – Shushary | 26.2 (16.3) | 1997–2019 |
| Line 1 | Suzhou Metro | China | Mudu – Zhongnan Jie | 25.7 (16.0) | 2012 |
| Line 3 | Athens Metro | Greece | Dimotiko Theatro – Doukissis Plakentias | 25.3 (15.72) | 2023 |
| Helsinki Metro | Helsinki Metro | Finland | Kalasatama – Kivenlahti | 25.2 (15.7) | 1982–2022 |
| Orange Line | Taipei Metro | Taiwan | Huilong–Nanshijiao | 25.1 (15.6) (longest branch) | 1998–2013 |
| Line 3 | Santiago Metro | Chile | Plaza de Quilicura - Fernando Castillo Velasco | 25 (13.5) | 2019–2023 |
| Yurakucho Line | Tokyo Metro | Japan | Chikatetsu Narimasu – Tatsumi | 24.6 (15.3) | 1974–1988 |
| U2 | Munich U-Bahn | Germany | Feldmoching – Messestadt Ost | 24.4 (15.2) | 1980–2001 |
| Yellow Line | Delhi Metro | India | GTB Nagar – Saket | 24 (14.9) | 2009–2010 |
| L-1 | Madrid Metro | Spain | Valdecarros – Pinar de Chamartín | 23.88 (14.84) | 1919–2007 |
| L-6 | Madrid Metro | Spain | Circle route | 23.47 (14.58) | 1979–2007 |
| Line 9 | Shanghai Metro | China | Jiuting – Middle Yanggao Road | 23.3 (14.48) | 2007–2010 |
| Line 1 Green | Montreal Metro | Canada | Angrignon – Honoré-Beaugrand | 23.26 (14.45) | 1966–1978 |
| Warsaw Metro M1 | Warsaw Metro | Poland | Kabaty–Młociny | 23.1 (14.35) | 1995–2008 |
| Line 2 | Beijing Subway | China | Circle route | 23.1 (14.35) | 1984–1987 |
| M3 | Istanbul Metro | Turkey | Bakırköy Sahil – Şehir Hastanesi Viaduct | 22.6 (16.6) | 2013–2024 |
| Line 9 | Chengdu Metro | China | Phase 1 of the second loop line in Chengdu, all underground | 22.18 km (13.78 mi) | 2020 |
| Line 19 | Beijing Subway | China | Mudanyuan – Xingong | 22.4 (13.9) | 2021 |
| Songshan-Xindian Line (Taipei Metro Green Line) | Taipei Metro | Taiwan | Songshan-Xindian | 21.3 (13.2) | 1998–2014 |
| Line 4 | Shanghai Metro | China | Hailun Road – Yishan Road | 21.1 (13.11) | 2005–2007 |
| Toei Mita Line | Toei Subway | Japan | Meguro – Shimura-Sakaue | 21.1 (13.11) | 1968–2000 |
| Victoria line | London Underground | United Kingdom | Walthamstow Central – Brixton | 21.0 (13.05) | 1968–1971 |
| Obolonsko–Teremkivska line | Kyiv Metro | Ukraine | Heroiv Dnipra–Teremky | 20.95 (13.02) | 1976–2013 |
| Line 6 | Shanghai Metro | China | Boxing Road – Oriental Sports Center | 20.34 (12.64) | 2007–2011 |
| Line 1 | Barcelona Metro | Spain | Fondo – Hospital de Bellvitge | 20.2 (12.56) | 1926–1989 |
| Tozai Line | Sapporo Municipal Subway | Japan | Miyanosawa – Shin-Sapporo | 20.1 (12.4) | 1976–1999 |
| M1 | Ankara Metro | Turkey | Koru – Atatürk Kültür Merkezi | 20.1 (12.4) | 1997–2014 |
| L-5 | Madrid Metro | Spain | Alameda de Osuna – Empalme | 20.005 (12.5) | 1968–2006 |
| Line 9 | Barcelona Metro | Spain | Zona Universitaria – Aeroport T1 | 20.0 (12.5) | 2004–2016 |
| North East MRT line | Mass Rapid Transit (Singapore) | Singapore | HarbourFront–Punggol | 20.0 (12.43) | 2003–2011 |
| Bucharest Metro Line M3 | Bucharest Metro | Romania | Preciziei – Anghel Saligny | 20.0 (12.43) | 1983–2008 |
| Line 7 (longest branch) | Paris Métro | France | La Courneuve–8 mai 1945 – Villejuif–Louis Aragon | 19.8 (12.3) | 1910-1987 |
| Line 2 | Tianjin Metro | China | Caozhuang – Guoshanlu | 19.7 (12.2) | 2012–2014 |
| Nekrasovskaya line | Moscow Metro | Russia | Nizhegorodskaya – Nekrasovka | 19.6 (12.2) | 2019–2020 |
| Line 9 | Paris Métro | France | Pont de Sèvres – Mairie de Montreuil | 19.6 (12.2) | 1922–1937 |
| M2 | Istanbul Metro | Turkey | Şişhane – Hacıosman Line is 23,49 km long, but the longest continuous underground section is 19.54 km long. | 19.54 (12.14) | 2000–2014 |
| Red, Yellow, Blue, and Green Lines | Bay Area Rapid Transit, San Francisco | United States | Balboa Park – West Oakland | 19.5 (12.12) | 1973 |
| Metro Northwest | Sydney Metro | Australia | Cherrybrook–Chatswood | 19.5 km (12.1 mi) | 2009–2019 |
| Kol'tsevaya Line | Moscow Metro | Russia | Circle route | 19.4 (12.2) | 1950–1954 |
| U3 | Munich U-Bahn | Germany | Moosach – Fürstenried West | 19.4 (12.05) | 1972–2009 |
| Line 4 | Tianjin Metro | China | Dongnanjiao – Xinxingcun | 19.4 (12) | 2021 |
| Line 3 | Tianjin Metro | China | Huayuan – Tianshili | 19.2 (11.9) | 2012–2013 |
| Maskoŭskaja line | Minsk Metro | Belarus | Malinawka–Uruchcha | 19.1 (11.9) | 1984–2014 |
| Midosuji Line | Osaka Metro | Japan | Nakatsu – Nakamozu | 19.1 (11.87) | 1933–1987 |
| Line 5 | Barcelona Metro | Spain | Vall d'Hebron – Cornella centre | 19.0 (11.8) | 1955–2010 |
| Warsaw Metro M2 | Warsaw Metro | Poland | Bemowo–Bródno | 18.9 km (11.7 mi) | 2015–2022 |
| Mexico City Metro Line 3 | Mexico City Metro | Mexico | La Raza – Universidad | 18.7 (11.62) | 1970–1983 |
| Red Line | Baku Metro | Azerbaijan | Icheri Sheher – Hazi Aslanov | 18.6 (11.6) | 1967–2002 |
| Line 7 (shorter branch) | Paris Métro | France | La Courneuve–8 mai 1945 – Mairie d'Ivry | 18.5 (11.5) | 1910-1987 |
| Line 3 | Barcelona Metro | Spain | Zona Universitària – Trinitat Nova | 18.4 (11.44) | 1925–2008 |
| Line 1 | Shanghai Metro | China | Shanghai South Railway – Shanghai Circus World | 18.1 (11.25) | 1993–2004 |
| Avtozavodskaya Line | Minsk Metro | Belarus | Kamennaya Gorka – Mogilevskaya | 18.1 (11.25) | 1990–2005 |
| U8 | Berlin U-Bahn | Germany | Wittenau – Hermannstraße | 18.1 (11.25) | 1927–1996 |
| Line B | Prague Metro | Czechia | Rajská zahrada – Hůrka | 18.0 (11.2) | 1998 |
| Line 2 | Athens Metro | Greece | Anthoupoli – Elliniko | 17.9 (11.12) | 2013 |
| Line 5 | Beijing Subway | China | Huixin Xijie Beikou – Songjiazhuang | 17.8 (11.1) | 2007 |
| Washington, DC Metro Red Line | Washington Metro | United States | Union Station – Medical Center | 17.8 (11.05) | 1984 |
| Line 15 | Beijing Subway | China | Qinghua Donglu Xikou – Maquanying | 17.6 (10.9) | 2014 |
| Tozai Line | Kyoto Municipal Subway | Japan | Uzumasa Tenjingawa-Yamashina-Rokujizo | 17.5 (10.92) | 2008 |
| Line 27 | Chengdu Metro | China | Shuxin Road - Fanjia Alley | 17.34 km (10.77 mi) | 2024 |
| Line 4 | Barcelona Metro | Spain | Trinitat Nova – La Pau | 17.3 (10.76) | 1908–1999 |
| Kholodnohirsko–Zavodska line | Kharkiv Metro | Ukraine | Kholodna Hora – Industrialna | 17.3 (10.7) | 1975–1978 |
| Line 12 | Paris Métro | France | Mairie d'Aubervilliers – Mairie d'Issy | 17.2 (10.7) | 1910–2022 |
| Milan Metro M3 | Milan Metro | Italy | Comasina – San Donato | 17.105 (10.62) | 1990–2011 |
| Bucharest Metro Line M2 | Bucharest Metro | Romania | Pipera – Berceni | 17.1 (10.62) | 1986–1987 |
| Tōzai Line | Tokyo Metro | Japan | Nakano–Minami-Sunamachi | 17.0 (10.56) | 1969 |
| M1 | İzmir Metro | Turkey | Kaymakamlık – Basmane Line is 27 km long, but only 19.8 km of it is underground in two noncontinuous sections. The shorter underground section is 2.9 km long. | 16.9 (10.5) | 2000–2024 |
| Line 13 (longest branch) | Paris Métro | France | Malakoff–Plateau de Vanves – Saint-Denis-Université | 16.8 (10.5) | 1911–1998 |
| Hanzomon Line | Tokyo Metro | Japan | Shibuya-Oshiage | 16.8 (10.4) | 1978–2003 |
| Mexico City Metro Line 1 | Mexico City Metro | Mexico | Observatorio – Pantitlán | 16.7 (10.38) | 1984 |
| Blue Line | Chennai Metro | India | Saidapet - Tondiarpet | 16.6 (10.32) | 2018–2021 |
| Line 9 | Beijing Subway | China | National Library – Guogongzhuang | 16.5 (10.3) | 2012 |
| Line 17 | Beijing Subway | China | Shilihe – Jiahuihu | 16.5 (10.3) | 2021 |
| L-3 | Madrid Metro | Spain | Villaverde Alto – Moncloa | 16.42 (10.2) | 2007 |
| Line 1 | Chongqing Rail Transit | China | Chaotianmen – Shapingba | 16.4 (10.2) | 2011 |
| Line A | Prague Metro | Czechia | Nemocnice Motol – Depo Hostivař Line is 17.1 km long, but only 16.4 km of it is underground. | 16.4 (10.2) | 2015 |
| Kalininskaya line | Moscow Metro | Russia | Tretyakovskaya – Novokosino | 16.3 (10.1) | 1979–2012 |
| Line 8 | Paris Métro | France | Balard – Charenton–Écoles | 16.2 (10.1) | 1913–1942 |
| Metro City | Sydney Metro | Australia | Chatswood – Sydenham | 16 km (9.9 mi) | 2024 |
| L-4 | Madrid Metro | Spain | Argüelles – Pinar de Chamartín | 16.0 (9.9) | 2007 |
| Sviatoshynsko–Brovarska line | Kyiv Metro | Ukraine | Akademmistechko–Dnipro | 16.0 (9.9) | 1960–2003 |
| Seoul Subway Line 7 (shorter section) | Seoul Subway | South Korea | Suraksan – Konkuk University | 16.0 (9.9) | 1996 |
| U6 | Berlin U-Bahn | Germany | Alt-Mariendorf – Kurt-Schumacher-Platz | 15.9 (9.86) | 1923–1966 |
| M9 | Istanbul Metro | Turkey | Ataköy – Olimpiyat Viaduct | 15.8 (9.8) | 2013–2024 |
| Line B | Toulouse Metro | France | Borderouge to Ramonville | 15.7 (9.8) | 2007 |
| M3 Line | Copenhagen Metro | Denmark | Circle route | 15.5 km (9.6 mi) | 2019 |
| Line 3 | Budapest Metro | Hungary | Határ út–Újpest-központ Line is 17.39 km long, but only 15.5 km of it is underground. | 15.5 km (9.6 mi) | 1990 |
| Line 1 | Tianjin Metro | China | Qinjiandao – Tucheng | 15.37 (9.55) | 2006 |
| Line 6 | Santiago Metro | Chile | Cerrillos – Los Leones | 15.3 (9.5) | 2017 |
| Syretsko–Pecherska line | Kyiv Metro | Ukraine | Syrets – Pivdennyi Bridge | 15.2 (9.4) | 1989–2004 |
| Blue Line | Kolkata Metro | India | Mahanayak Uttam Kumar -Dum Dum | 15.17 (9.38) | 1984–1995 |
| Line 10 | Chengdu Metro | China | Taipingyuan – Shuangliu West Railway Station | 15.0 (9.32) | 2019 |
| Island line | MTR | Hong Kong | Kennedy Town – Heng Fa Chuen | 15.0 (9.32) | 1985 (as Hong Kong)–2014 |

## World's longest subway tunnel sections under construction

| Name | System | Country | Stations | Length | Expected completion |
| Line 15 | Paris Métro | France | Noisy–Champs - Champigny Centre Circle route, all underground | 75 km (47 mi) | Southern section: 2025 Full line: 2031 |
| M11 | Istanbul Metro | Turkey | (Phase 2, Kargo Terminali - Halkalı section is 31.5 km in length and is currently under construction, all underground) | 69 km (43 mi) | Phase 2：2024 Full line: 2025 |
| Cross Island line | Mass Rapid Transit (Singapore) | Singapore | Linear route with branch section, all underground (Excludes potential extension from Punggol to Seletar Airport under planning) | 65.5 km (40.7 mi) | 2030–2032 |
| Line 13 | Guangzhou Metro | China | Whole lines is underground (includes Phase II: Chaoyang – Zhucun is 33.6 km and under construction) | 59.2 km (36.8 mi) | Phase 1：2017 Phase 2：2026 |
| L9 / L10 | Barcelona Metro | Spain | | 47.8 km (29.7 mi) (incl. branches) | 2009 and 2016 partially; central section: 2028–2029 |
| Line 13 | Shenzhen Metro | China | Whole line is underground | 45.72 km (28.41 mi) | Phase 1：2024 Phase 2 (North extension)：2025 South extension：2026 |
| Thomson–East Coast line | Mass Rapid Transit (Singapore) | Singapore | Woodlands North to Sungei Bedok (Phases 4 and 5, Gardens by the Bay – Sungei Bedok are 13 km in length and are currently under construction, all underground) | 43.4 km (27.0 mi) | Phase 4：2024 Phase 5：2025 |
| Line 22 | Shanghai Metro | China | Jinji Road - Dongtan | 40.9 km | 2026 |
| Troitskaya line | Moscow Metro | Russia | Whole line is underground | 40.2 km (25.0 mi) | Phase 1：2024 (25 km (16 mi)) Phase 2：2028–2029 (15.2 km (9.4 mi)) |
| Athens Metro Line 4 | Athens Metro | Greece | | 38.2 km (23.7 mi) | 2029 for Phase 1 |
| Line 12 | Guangzhou Metro | China | Xunfenggang – Higher Education Mega Center South | 37.6 km (23.36 mi) | 2025 |
| Metro Manila Subway | Manila Metro Rail Transit System | Philippines | Mindanao Avenue – Ninoy Aquino International Airport (All underground) | 36 km (22 mi) | 2029 |
| Line 22 | Shenzhen Metro | China | Shangsha - Liguang | 34.2km | Phase 1: 2029 |
| Line 3 | Mumbai Metro | India | Cuffe Parade-SEEPZ | 33.02 km (20.52 mi) | 2025 for Phase 1 |
| Line 6 | Nanjing Metro | China | Whole line is underground | 32.4 km | |
| Line 15 | Shenzhen Metro | China | Whole line is underground | 32.2 km (20.0 mi) | 2028 |
| Line 13 | Chengdu Metro | China | Qiligou – Longhua Temple underground section | 29.07 km (18.06 mi) | 2025 |
| Line 16 | Paris Métro | France | Saint-Denis–Pleyel - Noisy–Champs All underground | 27.5 km (17.1 mi) | Phase 1: 2026 Phase 2: 2028 |
| Line 3 | Chennai Metro | India | Madhavaram Milk Colony – Tharamani | 27.086 km (16.830 mi) | 2026–2027 |
| D Line Extension | Los Angeles Metro | United States | Westwood/VA Hospital – Union Station | 24.3 km (15.1 mi) | 2025–2026 |
| Line 30 | Chengdu Metro | China | (Phase 1 is 26.28 km) | 26.28 km (16.33 mi) | 2025 |
| Suburban Rail Loop | Melbourne rail network | Australia | SRL East and North is underground (Cheltenham to Airport) | 26 km (16 mi) | 2035 (Eastern stretch) |
| Metro West | Sydney Metro | Australia | | 24 km (15 mi) | 2032 |
| Metro Western Sydney Airport | Sydney Metro | Australia | | 23 km (14 mi) | 2026 |
| Line C | Toulouse Metro | France | Underground from Colomiers Gare to Montaudran Gare, full line will be 27 km long. | 22 km (14 mi) | 2028 |
| Blue Line | Stockholm Metro | Sweden | The extension to Nacka will be around 8 km, all underground, total 22 km including older sections. | 22 km (14 mi) | 2030 |