Line 3

3 Line or Line 3 may refer to:

Asia

 * Line 3 (Chennai Metro), or Purple Line, under construction in India
 * Line 3 (Kolkata Metro), under construction in Kolkata, India.
 * Line 3 (Mumbai Metro), under construction in India
 * Line 3 (Pune Metro), under construction in India
 * Ampang Line or Line 3, in Klang Valley, Malaysia
 * MRT Line 3 (Metro Manila), Philippines
 * Busan Metro Line 3, in South Korea
 * Seoul Subway Line 3, in South Korea
 * Taipei Metro Line 3 or Songshan–Xindian or Green line, in Taiwan
 * Line 3 (Hanoi Metro) or Văn Miếu Line, under construction in Vietnam

China

 * Line 3 (Beijing Subway), a subway line under construction in Beijing
 * Line 3 (Changchun Rail Transit), a light rail line in Changchun, Jilin
 * Line 3 (Changsha Metro), a metro line in Changsha, Hunan
 * Line 3 (Chengdu Metro), a metro line in Chengdu, Sichuan
 * Line 3 (Chongqing Rail Transit), a monorail line in Chongqing
 * Line 3 (Dalian Metro), a metro line in Dalian, Liaoning
 * Line 3 (Dongguan Rail Transit), a planned metro line in Dongguan, Guangdong
 * Line 3 (Foshan Metro), a metro line in Foshan, Guangdong
 * Line 3 (Guangzhou Metro), a metro line in Guangzhou, Guangdong
 * Line 3 (Hangzhou Metro), a metro line in Hangzhou, Zhejiang
 * Line 3 (Harbin Metro), a metro line in Harbin, Heilongjiang
 * Line 3 (Hefei Metro), a metro line in Hefei, Anhui
 * Line 3 (Jinan Metro), a metro line in Jinan, Shandong
 * Line 3 (Kunming Metro), a metro line in Kunming, Yunnan
 * Line 3 (Nanchang Metro), a metro line in Nanchang, Jiangxi
 * Line 3 (Nanjing Metro), a metro line in Nanjing, Jiangsu
 * Line 3 (Nanning Metro), a metro line in Nanning, Guangxi
 * Line 3 (Ningbo Rail Transit), a metro line in Ningbo, Zhejiang
 * Line 3 (Qingdao Metro), a metro line in Qingdao, Shandong
 * Line 3 (Shanghai Metro), a metro line in Shanghai
 * Line 3 (Shenzhen Metro), a metro line in Shenzhen, Guangdong
 * Line 3 (Shijiazhuang Metro), a metro line in Shijiazhuang, Hebei
 * Line 3 (Suzhou Rail Transit), a metro line in Suzhou, Jiangsu
 * Line 3 (Tianjin Metro), a metro line in Tianjin
 * Line 3 (Wuhan Metro), a metro line in Wuhan, Hubei
 * Line 3 (Wuxi Metro), a metro line in Wuxi, Jiangsu
 * Line 3 (Xiamen Metro), a metro line in Xiamen, Fujian
 * Line 3 (Xi'an Metro), a metro line in Xi'an, Shaanxi
 * Line 3 (Xuzhou Metro), a metro line in Xuzhou, Jiangsu
 * Line 3 (Zhengzhou Metro), a metro line in Zhengzhou, Henan

Europe

 * Line 3 (Athens Metro), a metro line of the Athens Metro, Athens, Greece
 * Line 3 (Budapest Metro), a subway line of the Budapest Metro, Budapest, Hungary
 * Line 3 (Madrid Metro), a metro line of the Madrid Metro, Madrid, Spain
 * Line 3 (Metrovalencia), in Valencia, Spain
 * Line 3 (Moscow Metro), the Arbatsko-Pokrovskaya line in Moscow, Russia
 * Line 3 (Saint Petersburg Metro)
 * Île-de-France tramway Line 3, a modern tramway in Paris
 * Paris Métro Line 3, a line of the Paris Métro rapid transit system in France
 * U3 (Vienna U-Bahn), a subway line of Vienna U-Bahn, Vienna, Austria

Canada

 * Line 3 Scarborough, a former intermediate capacity rapid transit line in Toronto
 * Line 3 Red (Montreal Metro), proposed but not built
 * Line 3 Ontario, an under construction subway line in Toronto

Mexico

 * Mexico City Metro Line 3, a rapid transit line in Mexico City
 * Mexico City Metrobús Line 3, a bus rapid transit line in Mexico City
 * Line 3 of the Guadalajara urban rail system, Mexico

United States

 * Route 3 (MTA Maryland), a bus route
 * 3 (New York City Subway service), a rapid transit service
 * 3 (Los Angeles Railway), former streetcar service
 * 3 Line (Sound Transit), a future light rail line in Seattle, Washington

South America

 * Line 3 (Metrovía), a bus route in Guayaquil, Ecuador
 * Line 3 (Rio de Janeiro), a proposed metro line in Rio de Janeiro, Brazil
 * Line 3 (São Paulo Metro), Brazil
 * Santiago Metro Line 3, in Chile

Australia

 * L3 Kingsford Line, light rail line in Sydney, New South Wales
 * T3 Bankstown Line, Sydney Trains service prior to 2024
 * T3 Liverpool & Inner West Line, 2024–