When opened as part of the Metro Tunnel project, Town Hall will be an underground premium station, featuring an island platform with two faces.

[7] Updated designs were revealed by the government in 2018 that showed Town Hall and State Library stations would feature large platform caverns with archways, and that there would be multiple entrances.

[10][11][12] In May 2020, major traffic changes were put in place near Flinders Street in order to improve safety around large trucks entering acoustic sheds as a part of the project.

[21] Initially it was planned to build the station using the cut-and-cover method, however this was changed so that the tunnels would run deeper underneath the ground in order to not disturb services, utilities and businesses on Swanston Street.

[22][23] Like State Library station, Town Hall used a unique "trinocular" construction method involved the mining of three large, overlapping tunnels with vaulted ceilings.

[31] In 2024, Rail Projects Victoria stated that this commission had been cancelled due to difficulties from the COVID-19 pandemic, and unlike the other stations Town Hall would not have its own artwork.

[33][19] The famous statue of ill-fated explorers Burke and Wills was removed from City Square in 2017 and is planned to return to the corner of Collins and Swanston Streets after the completion of the station.

[26] There will be 70 new bike parking spaces built to cope with increasing demand, as well as improved tram interchanges on Flinders, Collins, and Swanston streets.