Education had been carried on in Coleraine for many years by the Irish Society and by various private schools but around the middle of the 19th century some townspeople felt that there was a need for a local school where the sons of middle class families could obtain a classical education and one that would fit them for a career in business. The Irish Society provided a grant and the Clothworkers Company, who owned the land, gave a 5-acre site. The first proposals for what became Coleraine Academical Institution were made in 1846 but had to be laid aside during the period of the Great Irish Famine.
The school was built over a seven year period from 1854 to 1860. In May 1860 the school opened in the original building facing the river. The original building comprised “dining and common halls, two schoolrooms, a museum, a laboratory and a schoolmaster's house", and the first intake consisted of two masters and fourteen boys. In 1876 a large wing was added, followed in 1880 by a sanatorium and in 1882 by a gymnasium. In 1894 a four storey building with basement was added, known variously as 'the Old Boys Wing' and - latterly - 'the Gods'. Due to instability, its top storey was removed in 1929 and replaced by a hipped roof, but to this day it remains the most conspicuous landmark.
During his time as Headmaster which included part of the fifties, sixties and seventies, Dr Humphreys guided a vast physical expansion of the school and was invited into membership of the Headmasters Conference, and the Inst became an 'H.M.C', or Public School.
The present range of school sports is housed on an estate with ten rugby pitches, five cricket wickets, five tennis counts, a sports hall, a boathouse, an indoor swimming pool and a hard running track and field athletics area.
The original school sports were cricket and athletics, but competitive rugby and rowing seem to have started later. The first recorded rowing race took place in 1929 against Portora Royal School in the Wray Cup. In this period the school boys rowed from Bann Rowing Club’s boathouse until 1968 when the school’s River Pavilion was opened by HRH the Duke and Duchess of Kent. Along with an extension added in later years, the boathouse on the ground floor of the River Pavilion is still the home of C.A.I.B.C. today.