The ship was decommissioned on 23 September 1923 following the Washington Naval Treaty of 1922 and scheduled for destruction.
However, at the request of the Japanese government, each of the signatory countries to the treaty agreed that Mikasa could be preserved as a memorial ship with her hull encased in concrete.
On 12 November 1926, Mikasa was opened for display in Yokosuka in the presence of Crown Prince Hirohito and Tōgō.
Following the surrender of Japan in 1945, the ship deteriorated under control of the occupation forces.
In 1955, Philadelphia businessman John Rubin, formerly of Barrow, England, wrote a letter to the Japan Times about the state of the ship, which was the catalyst for a new restoration campaign.
With the support of the Japanese public, and also Fleet Admiral Chester W. Nimitz, the restored battleship reopened in 1961.
On 5 August 2009, Mikasa was repainted by sailors from USS Nimitz.

Mikasa is remembered in Barrow-in-Furness, the town of its construction, by Mikasa Street on Walney Island.
The ship was decommissioned on 23 September 1923 following the Washington Naval Treaty of 1922 and scheduled for destruction. However, at the request of the Japanese government, each of the signatory countries to the treaty agreed that Mikasa could be preserved as a memorial ship with her hull encased in concrete. On 12 November 1926, Mikasa was opened for display in Yokosuka in the presence of Crown Prince Hirohito and Tōgō. Following the surrender of Japan in 1945, the ship deteriorated under control of the occupation forces. In 1955, Philadelphia businessman John Rubin, formerly of Barrow, England, wrote a letter to the Japan Times about the state of the ship, which was the catalyst for a new restoration campaign. With the support of the Japanese public, and also Fleet Admiral Chester W. Nimitz, the restored battleship reopened in 1961. On 5 August 2009, Mikasa was repainted by sailors from USS Nimitz.
Mikasa is remembered in Barrow-in-Furness, the town of its construction, by Mikasa Street on Walney Island.
Japanese battleship Mikasa