The Proastiakos (Greek: Προαστιακός; "suburban") is Greece's Commuter rail service, run by Hellenic Train, on rail infrastructure owned by the Hellenic Railways Organisation (OSE) (lines) and GAIAOSE (buildings and Trains).

[1] As of 8 January 2017, the lines between the central stations of Athens and Halkida have been electrified, allowing EMU train service.

In July 2010, a new commuter rail service was launched in Patras on a section of the old Patras–Kyparissia line[2] reconnecting the city with Rio.

During the construction of Attiki Odos motorway in the late 1990s, space was left between the main carriageways for the railway line.

The first suburban services between Athens and the Airport were inaugurated using Stadler GTW and Siemens Desiro DMU trains.

On 27 September 2005, the new standard gauge rail line reached Corinth, terminating at a new station, located at Examilia.

[4] Hellenic Train also runs "Proastiakos" commuter rail services between the cities of Thessaloniki[5] and Larissa, on the modernised and electrified main line.

In May 2020 TrainOSE updated its electronic ticketing system to support social distancing on all Proastiakos services.

The system stopped selling tickets when capacity on that train had reached 50 percent, TrainOSE CEO Filippos Tsalidis told reporters during a press briefing on safety measures to prevent Covid-19 infection during travel.

[9] According to a TrainOSE spokesperson, the interruption is due to technical problems; however no information on the progress of any work was given,[9] services were rerouted via SKA.

In the early phase of operation, trains run from Kato Achaia to Patras Central Station.

[21] This special schedule is organised in order to help visitors move around the city and its suburbs during the Patras Carnival going on that weekend.

Although regular passenger service will not see trains running in the evening, it is expected that from May onwards, when the tourist and summer season begins, trains will run hourly back and forth in order to accommodate the increased passenger flows towards the popular summer spots in Western Achaia.

These are: (*)A bus shuttle service will run from Tsoukaleika to the Patras Industrial Area, serving people who work there.

The outbreak of the COVID-19 pandemic and the subsequent lockdown imposed made things worse for that line, and shortly after, services were suspended indefinitely.

Five days earlier, on 4th July, after the lockdown was lifted, services on the South sector recommenced,[22] albeit on a shorter route.

The new service from Agios Andreas to Kaminia saw trains initially run hourly from 6:30 till 15:00.

In late 2020 however, TrainOSE announced plans to purchase new rolling stock which will consist of double decker EMU's, preferably from the Italian market.

Addition of new routes and stations to Proastiakos services depends on the progress of a number of OSE infrastructure projects in Attica.

The line to Rafina shall branch off after Pallini station and will partly run on the central reservation of the Hymittus Ring Road.

They shall be served by Proastiakos suburban trains in the future, when electrification and adequate line capacity are available between Athens and SKA.