List of metro systems

This list of metro systems includes electrified rapid transit train systems worldwide. In some parts of the world, metro systems are referred to as subways, undergrounds, tubes, mass rapid transit (MRT), metrô or U-Bahn. As of 1 April 2025, 204 cities in 65 countries operate 891 metro lines.
The London Underground first opened as an underground railway in 1863 and its first electrified underground line, the City and South London Railway, opened in 1890, making it the world's first deep-level electric metro system. The Budapest Millennium Underground Railway, which opened in 1896, was the world's first electric underground railway specifically designed for urban transportation and is still in operation today. The Shanghai Metro is both the world's longest metro network at 808 kilometres (502 mi) and the busiest with the highest annual ridership reaching approximately 2.83 billion passenger trips. The Beijing Subway has the greatest number of stations, with 424. As of 2024, the country with the most metro systems is China, with 54 in operation, including 11 of the 12 longest networks in the world.
The International Association of Public Transport (L'Union Internationale des Transports Publics, or UITP) defines metro systems as urban passenger transport systems, "operated on their own right of way and segregated from general road and pedestrian traffic". The terms heavy rail (mainly in North America) and heavy urban rail are essentially synonymous with the term "metro". Heavy rail systems are also specifically defined as an "electric railway".
The dividing line between the metro and other modes of public transport, such as light rail and commuter rail, is not always clear. The UITP only makes distinctions between "metros" and "light rail", whereas the American Public Transportation Association (APTA) and Federal Transit Administration (FTA) distinguish all three modes. A common way to distinguish metro from light rail is by their separation from other traffic. While light rail systems may share roads with car traffic or use sections of track with level crossings across roads, metro systems tend to run on a grade-separated exclusive right-of-way with no access for other traffic.
In contrast to commuter rail or light rail, metro systems are primarily used for transport within a city, and have higher service frequencies and substantially higher passenger volume capacities. Most metro systems do not share tracks with freight trains or inter-city rail services. It is not relevant whether the system runs on steel wheels or rubber tyres, or if the power supply is from a third rail or overhead line.
The name of the system is not a criterion for inclusion or exclusion. Some cities use "metro" as a brand name for a transit line with no component of rapid transit whatsoever. Similarly, there are systems branded "light rail" that meet every criterion for being a rapid transit system. Some systems also incorporate light metro or light rail lines as part of the larger system under a common name. These are listed, but the light rail lines are not counted in the provided network data.
Certain transit networks may match the service standards of metro systems, but reach far out of the city and are sometimes known as S-Bahn, suburban, regional or commuter rail. These are not included in this list. Neither are funicular systems, or people movers, such as amusement park, ski resort and airport transport systems.
This list counts metros separately when multiple metros in one city or metropolitan area have separate owners or operating companies. This list expressly does not aim at representing the size and scope of the total rapid transit network of a certain city or metropolitan area. The data in this list should not be used to infer the size of a city's, region's, or country's urban rail transit systems, or to establish a ranking.
This list is sortable. Click on the icon in the column header to change sort key and sort order. Note: This list may not be fully representative, as yearly ridership numbers during the COVID-19 pandemic are shown for some systems, while others have numbers from previous years.
Recent ridership figures, particularly for 2020, will have been affected by the COVID-19 pandemic.
The following is a list of new worldwide metro systems that are currently actively under construction. In some cases it is not clear if the system will be considered a full metro system once it begins operational service. Only metro systems under construction are listed where there are no metro systems currently in operation in the same city.
The countries of Iraq, Israel, Ivory Coast and Serbia are currently constructing their first ever metro systems.