The final alignment corresponds with "option B" of the 2005 revised scheme, with no intermediate station at Happy Valley included, in order to reduce the travel time to the central business district.

The final order for rolling stock for the new line consisted of 10 new three-car MTR CNR Changchun EMUs using steel wheels.

[7] In August 2012, drilling and blasting work began for constructing the Nam Fung Tunnel, between Admiralty and Ocean Park stations.

[15] Eight days later at the South District Council meeting, MTRC announced the delay was caused by the expansion work of Admiralty station.

High-density building, underground public facilities and the existing Admiralty station would prolong the work progress, as "safety comes first".

[17] In October 2016, MTRC chairman Frederick Ma warned that the opening of the South Island line could be delayed by three more months.

[18] However, on 10 November 2016, he announced the South Island line would open by the end of 2016, saying the engineering team overcame the many challenges in expanding Admiralty Station.

[19] Finally, MTRC chief executive Lincoln Leong officially declared the South Island line would begin operation on 28 December 2016.

MTR managerial officials, including CEO Lincoln Leong, welcomed passengers and rode on the first departure.

[20] However, the day after the line opened, an electrical fault triggered power outages at 2:15 pm, causing lighting systems, escalators, elevators, and fare gates to stop working.