He was, at one time, a Member of the Executive Council of the World Assembly of Judges and of the Managing Committee of the British Institute of International and Comparative Law. He was a Member of the International Council of Former Scouts and Guides, Brussels, and Chief Scout of the Boy Scouts Association of India. Post-retirement, Hidayatullah renewed his interest in Boy Scouts and served as Chief Scout of the All India Boy Scouts Association from 1982 to 1992. He held the posts of the President of Bombay Natural History Society and of the Patron of Schizophrenic Research Foundation of India and Commonwealth Society of India. He was also a Member of the World Association for Orphans and Abandoned Children and a Settlor of the Jawaharlal Nehru Cambridge University Trust. He also represented India in International Conferences held in different countries and cities, such as,