After 67 prosperous years at Mutwal, S.Thomas’ College finally relocated to the sandy shores of Mount Lavinia in the year 1918 under the guidance of Warden W. A. Stone. The move from Mutwal was a long and arduous journey. However, with the help of Bishop E.A Copleston and Mr.C.E.A. Dias who contributed a large portion of their time and money to facilitate the transference, Warden Stone successfully moved the college from Mutwal to Mount Lavinia.
Despite the significant distance between Mutwal and Mount Lavinia, a majority of the boys chose to relocate to the new site. Upon arrival they did not encounter the picturesque campus that exists today but rather only the main class room block and the laboratory (the present library building), while the big club grounds was comprised largely of coconut trees. Throughout his tenure, Warden Stone took steps to ensure that the campus available to the students was extended. The first event of 1918 was the blessing of the College by the Bishop of Colombo on the 26th of January 1918. That service marked the beginning of what would become the first day of a 100 years of existence at Mount Lavinia and the passage of many generations of gentlemen produced from the halls of this hallowed institution.