Construction of the tunnels between the City Hall and Raffles Place stations required the draining of the Singapore River.

A designated Civil Defence shelter, the three-level station features a mural by Simon Wong which depicts government buildings in the area.

[6] It was renamed to City Hall in November that year for historical reasons and to better reflect the area served.

The gathering prayed for the safety of the cathedral and the construction workers, the successful completion of the station, and blessings for future commuters.

[15] The construction of tunnels between the City Hall and Raffles Place stations required the draining of the Singapore River.

[16] The contractor used the cut-and-cover construction method since the tunnels, which cross over one another, would pass through a shallow part of the river.

[17] The cofferdam in the first stage occupied about 20 metres (66 ft) of the river width from the riverbank at the Immigration Building site of Empress Place.

Another stoneware jar, which retained its original bronze glaze but was missing its handles, was also uncovered at the Empress Place site.

[21] The rest of the construction was completed in one stage, taking up the remaining 70 metres (230 ft) of the river width.

[24] The cathedral was eventually declared safe for use, and operations resumed on 2 June with the collapsed area backfilled.

[27] Train services commenced on 12 December 1987 when the line extension to Outram Park station was completed.

From 28 October 1989, it serves as the interchange station for both the East–West (EWL) and North–South (NSL) lines with the split of MRT operations.

[30] In addition to advertisement campaigns and guides about the transfers, Mass Rapid Transit Corporation (MRTC) staff were deployed at the platforms to help commuters.

As a CD shelter, the station has to be structurally reinforced against bomb attacks with layers of earth-backed, air-backed and airtight walls and slabs.

[1][51] Surrounding the station are cultural landmarks such as the former City Hall, Peranakan Museum, the Padang, St Andrew's Cathedral, National Gallery Singapore, Old Supreme Court Building, Supreme Court of Singapore, Parliament House and the Cenotaph.