Admiralty was always expected to be a transfer station to the Island line. On 31 May 1985, the first phase of the Island line (between Admiralty and Chai Wan) was opened, with Admiralty the temporary western terminus of the Island line. To facilitate cross-platform interchange, the Tsuen Wan- and Chai Wan-bound platforms were located on a very wide island platform on the lower level, while the Central-bound and termination platforms shared another very wide island platform on the upper level. When the second part of the Island line (Admiralty to Sheung Wan) opened in 1986, the termination platform became the Sheung Wan-bound platform, while the other platforms remained unchanged.