Currently, there is no urban rail transit system in Honolulu, although electric street railways were once used during the early days of Honolulu's history. The first major attempt was called the Honolulu Area Rail Rapid Transit (HART) project.

Originally proposed in 1968 by Mayor Neal S. Blaisdell and supported by his successor, Frank Fasi, HART was originally envisioned as a 29-mile (47 km) line from Pearl City to Hawaii Kai. By 1980, however, the project's length was cut to an 8-mile (13 km) segment between the University of Hawaii at Manoa and Honolulu International Airport.

In the wake of proposed budget cuts by President Ronald Reagan, newly elected Mayor Eileen Anderson cancelled the project in 1981 and returned grants and funding to their sources, arguing the project would break her vow of fiscal responsibility.

After defeating Anderson in 1984 to regain the mayorship, Fasi started plans to revive the HART project. Funding avenues that Fasi explored included a substantial (66 percent) increase in the gasoline tax and diversion of money earmarked for then-stalled Interstate H-3 to be used for the project.

In 1990, Governor John Waihee proposed allowing counties to collect a 0.5% increase in the excise tax to be used for transportation projects, and the state legislature approved the plan in May 1990. The counties would have until October 1, 1992 to enact the increase.

In October 1991, the Fasi administration chose Oahu Transit Group to develop the rail line, which was based on cars by AEG Westinghouse similar to those used in the San Francisco Bay Area Rapid Transit system. The U.S. House amended a transit bill to include $618 million for Honolulu's project, about one-third of the cost, and the Council in November entered into a joint funding agreement with the state.

On September 23, 1992, the city council voted 5-4 against enacting the tax increase, which effectively destroyed the project. Fasi made unsuccessful attempts to have a rail referendum (which was struck down by the courts), and to have private investors fund part of the line. The House revoked funding for the project on May 11, 1993, citing lack of guaranteed local funding.

In 2005, under the administration of Mufi Hannemann, the city, county and state approved development of an action plan for a unspecific rapid transit system, known as the "Honolulu High-Capacity Transit Corridor Project", to be built in several phases. The initial line proposed linking Kapolei in West Oahu to the University of Hawaii at Manoa. Then on December 22, 2006 the city council approved a fixed-guideway system meant to accommodate a rapid transit system of rail or buses, running from Kapolei in West Oahu to Ala Moana, with spurs into Waikiki and Manoa.

Opponents of the proposed rail system attempted to place a measure on the Honolulu ballot which would have prohibited any rail system from being used, but failed to gather the required signatures in time. In response, the Honolulu City Council voted to put a question on the Honolulu ballot which would direct the city transportation department to create a steel-wheel-on-steel-rail transit system.

On November 4, 2008, the residents of Honolulu voted to allow the process of developing the rail project to continue. The trains will be approximately 200 feet (61 m) long, electric, steel wheel to steel rail technology and will capable of carrying more than 300 passengers each. The measure passed with 52% of the vote.

The line is scheduled to open in five phases between 2012 and 2018:

2012: West Loch – Pearl Highlands

2013: East Kapolei – West Loch

2016: Pearl Highlands – Aloha Stadium (USS Arizona, and Pearl Harbor)

2017: Aloha Stadium – Middle Street (Honolulu International Airport)

2018: Middle Street – Ala Moana Center (Chinatown, Downtown, and Ala Moana Shopping Center)

The rail line, as currently planned, will be built starting from suburban areas in Kapolei and Ewa, and progressing towards the urban center in Honolulu. This is because the first phase includes a baseyard for trains, and a planning decision by the city to delay the major infrastructure impacts associated with construction in the urban center to later phases of the project.