On 1 June 1982, the test drives were opened to the general public.
Trains ran with passengers during the morning and afternoon rush hours between Itäkeskus and Hakaniemi (the Sörnäinen station was not yet opened at this time).
On 1 July the provisional service was extended to Rautatientori.
President of the Republic of Finland Mauno Koivisto officially opened the Metro for traffic on 2 August 1982 – 27 years after the initial motion to the city assembly had been made.

The Metro did not immediately win the approval from inhabitants of eastern Helsinki, whose direct bus links to the city centre had now been turned into feeder lines for the Metro.
Within six months of the Metro's official opening, a petition signed by 11,000 people demanded the restoration of direct bus links.
Subsequently, the timetables of the feeder services were adjusted and opposition to the Metro mostly died down.

On 1 March 1983 the Metro was extended in the west to Kamppi.
The Sörnäinen station, between Hakaniemi and Kulosaari, was opened on 1 September 1984.

The Metro was extended eastwards in the late 1980s, with the Kontula and Myllypuro stations opened in 1986, and the Mellunmäki station following in 1989.
The construction of a westwards expansion begun in 1987 with tunneling works from Kamppi towards Ruoholahti.
The Ruoholahti metro station was opened on 16 August 1993.

Another new station followed: the Kaisaniemi station, between Rautatientori and Hakaniemi, was opened on 1 March 1995.
It had in fact been decided on already in 1971, and the station cavern had been carved out of the rock during the original tunneling works, but a lack of funds had pushed back the station's completion.

On 31 August 1998, after four years of construction, the final section of the original plan was completed, with the opening of a three-station fork from Itäkeskus to Vuosaari.

The second generation of Metro trains to be used in passenger service (the M200 class) were delivered in 2000 and 2001 by Bombardier.
These trains are based on Deutsche Bahn's Class 481 EMUs used on the Berlin S-Bahn network.

On 25 September 2006, the city council of Espoo approved, after decades of debate, planning, and controversy, the construction of a western extension of the Metro.
Under the plan, Metro trains will run to Matinkylä by the end of 2017. (
See section The future below.)

On 1 January 2007, Kalasatama station, between the Sörnäinen and Kulosaari stations, was opened.
It serves the new "Sörnäistenranta-Hermanninranta" (Eastern Harbour) area, a former port facility that will be redeveloped as its functions are moved to the new Port of Vuosaari in the east of the city.

After 8 November 2009, the Rautatientori station, under the Central Railway Station, was closed to the public because a burst water pipe flooded it.
After renovations, the station reopened for public use on 15 February 2010.
The lifts were still under renovation, but they also reopened for service on 21 June 2010.
On 23rd August 2019 heavy rain caused again water damage on the Rautatientori station.
The station was opened in a few days but the lifts remained closed until 17th March 2020.
On 1 June 1982, the test drives were opened to the general public. Trains ran with passengers during the morning and afternoon rush hours between Itäkeskus and Hakaniemi (the Sörnäinen station was not yet opened at this time). On 1 July the provisional service was extended to Rautatientori. President of the Republic of Finland Mauno Koivisto officially opened the Metro for traffic on 2 August 1982 – 27 years after the initial motion to the city assembly had been made.
The Metro did not immediately win the approval from inhabitants of eastern Helsinki, whose direct bus links to the city centre had now been turned into feeder lines for the Metro. Within six months of the Metro's official opening, a petition signed by 11,000 people demanded the restoration of direct bus links. Subsequently, the timetables of the feeder services were adjusted and opposition to the Metro mostly died down.
On 1 March 1983 the Metro was extended in the west to Kamppi. The Sörnäinen station, between Hakaniemi and Kulosaari, was opened on 1 September 1984.
The Metro was extended eastwards in the late 1980s, with the Kontula and Myllypuro stations opened in 1986, and the Mellunmäki station following in 1989. The construction of a westwards expansion begun in 1987 with tunneling works from Kamppi towards Ruoholahti. The Ruoholahti metro station was opened on 16 August 1993.
Another new station followed: the Kaisaniemi station, between Rautatientori and Hakaniemi, was opened on 1 March 1995. It had in fact been decided on already in 1971, and the station cavern had been carved out of the rock during the original tunneling works, but a lack of funds had pushed back the station's completion.
On 31 August 1998, after four years of construction, the final section of the original plan was completed, with the opening of a three-station fork from Itäkeskus to Vuosaari.
The second generation of Metro trains to be used in passenger service (the M200 class) were delivered in 2000 and 2001 by Bombardier. These trains are based on Deutsche Bahn's Class 481 EMUs used on the Berlin S-Bahn network.
On 25 September 2006, the city council of Espoo approved, after decades of debate, planning, and controversy, the construction of a western extension of the Metro. Under the plan, Metro trains will run to Matinkylä by the end of 2017. (See section The future below.)
On 1 January 2007, Kalasatama station, between the Sörnäinen and Kulosaari stations, was opened. It serves the new "Sörnäistenranta-Hermanninranta" (Eastern Harbour) area, a former port facility that will be redeveloped as its functions are moved to the new Port of Vuosaari in the east of the city.
After 8 November 2009, the Rautatientori station, under the Central Railway Station, was closed to the public because a burst water pipe flooded it. After renovations, the station reopened for public use on 15 February 2010. The lifts were still under renovation, but they also reopened for service on 21 June 2010. On 23rd August 2019 heavy rain caused again water damage on the Rautatientori station. The station was opened in a few days but the lifts remained closed until 17th March 2020.
Helsinki Metro