Platforms 3 and 4 are built beneath King's Road to the south of Model Housing Estate.

The station was expanded in 1989 with the addition of platforms 3 and 4, which served as the terminus of Kwun Tong line upon the opening of the Eastern Harbour Crossing.

[3] On 27 September 2001, the Quarry Bay Congestion Relief Works was completed, extending the Kwun Tong line to North Point station and providing an easier and more spacious interchange there for Central bound passengers.

The station is noted for having the deepest platforms in the MTR network by metres above sea level to allow the Tseung Kwan O line tunnel to traverse Victoria Harbour.

This inconvenience and increasing passenger numbers were what prompted the MTRC to undergo the Quarry Bay Congestion Relief Works, which extended the Kwun Tong line one station to the west to North Point station, where cross-platform interchanges are provided.