In the years following World War I, the Edinburgh Royal Infirmary needed to expand once more and was interested in the site then occupied by Watson's.
At the same time, the Archibald Place building was cramped and in need of modernisation, as well as being distant from the school's playing fields at Myreside.
In 1924 the Merchant Company announced that they had taken the decision to sell the Archibald Place building to the Infirmary for a "fair" price.

In 1927, agreement was made to acquire the site of Merchiston Castle School – adjacent to the Myreside playing fields – and a competition was held to design the new school building.
The winner was announced in June 1928 as James B Dunn, himself a Watsonian, with a plan described as "simple, direct and masterly".

Building work on the new site commenced in August 1929.
The new building, facing Colinton Road, was in a neo-classical style and sandstone-faced.
It is H-shaped, extending over two stories, with a large central Assembly Hall which seats up to 1835.

The new building was completed in 1932.
It was opened on 22 September by HRH Prince George (later Duke of Kent).

The Golden Jubilee of the creation of the 1932 buildings fell in 1982, and was marked by a number of celebrations.
These culminated on 29 June with a visit from Her Majesty Queen Elizabeth.
The Queen spent two hours touring the campus, including a short concert, and she unveiled a commemorative plaque.
In the years following World War I, the Edinburgh Royal Infirmary needed to expand once more and was interested in the site then occupied by Watson's. At the same time, the Archibald Place building was cramped and in need of modernisation, as well as being distant from the school's playing fields at Myreside. In 1924 the Merchant Company announced that they had taken the decision to sell the Archibald Place building to the Infirmary for a "fair" price.
In 1927, agreement was made to acquire the site of Merchiston Castle School – adjacent to the Myreside playing fields – and a competition was held to design the new school building. The winner was announced in June 1928 as James B Dunn, himself a Watsonian, with a plan described as "simple, direct and masterly".
Building work on the new site commenced in August 1929. The new building, facing Colinton Road, was in a neo-classical style and sandstone-faced. It is H-shaped, extending over two stories, with a large central Assembly Hall which seats up to 1835.
The new building was completed in 1932. It was opened on 22 September by HRH Prince George (later Duke of Kent).
The Golden Jubilee of the creation of the 1932 buildings fell in 1982, and was marked by a number of celebrations. These culminated on 29 June with a visit from Her Majesty Queen Elizabeth. The Queen spent two hours touring the campus, including a short concert, and she unveiled a commemorative plaque.
George Watson's College