As reported in the Evening Herald 16 July 1969, eighty ex-Royal Hibernian old boys and their wives "...turned up for the happy occasion which marked the day 200 years ago when the world-famous Military School was founded. They came from all over England and Ireland and one ex-Royal Hibernian, 62-year-old Dick Howe flew the 12,000 miles from Los Angeles for the occasion."

Captain R. H. (Harry) Bloomer, from Glenegeary, Co. Dublin, organised the bi-centenary re-union in Dublin. The idea of the Phoenix Park re-union was first muted five years earlier. D. W. Roberts, English organizer and secretary, reported that the Old Boys Association (OBA) held a re-union in London every year, but for 1969 they were determined to hold it at their old school, which was converted into St. Mary's Hospital when they vacated the premises in 1922. Roberts collaborated with Frank Hawkins in writing the only known history of the Royal Hibernian school, which is now in the Library of the National Archives, Kew.

The boys had marched out of Phoenix Park in 1922 to temporary quarters in Shorncliffe, Kent. When the Royal Hibs were amalgamated with the Duke of York's school in 1924, the Hibernians held their last muster parade at which 233 boys were present in four companies – A, C, D and G – each 58 strong except that A Company had 59 boys in its ranks. Unlike the Duke of York's, whose companies were named after generals of the British Army, the Royal Hibernians stuck to their alphabetical designations. Although they had a regimental sergeant-major in RSM George Mason, Hibernian companies were under the command of sergeants: Colour Sergeants Carragher, Shuable, Allcock and McDermott. The Hibs also kept their Sergeant Bandmaster Thatcher and Sergeant Drummer Cochrane.

Eighty old boys and their wives gathered in Dublin for the bi-centenary year reunion. One ex-Hibernian, Dick Howe, age 62, had travelled from Los Angeles for the occasion. The oldest Hibernian present was 92-year-old Sergeant-Major A. M. Malone from Drumcondra. Also present was the former school chaplain from the 1920s, the Rev. Canon Furlong,

The 1969 re-union was not the last occasion the Hibernian OBA gathered together at Phoenix Park. A second, and apparently the last, meeting occurred in 1989 when 80 old boys again met at Phoenix Park. Captain Harry Bloomer, his wife Maureen and daughter Sheelagh organised the reunion as before. A party of 23 travelled from London, partly by air and partly by rail and sea. They were accommodated in the Montrose Hotel. A total of 121 old boys and their wives were present for a ceremony held at their old school and assembled under Colonel Paddy Cork, who was president for the occasion.