While in Dublin, Wachuku was an executive member of the Student Christian Movement (SCM). He lectured on various subjects at the SCM Summer Schools in Great Britain and Ireland; and delivered the last seven lectures at Swanwick, Hampshire, on the subject: "Africa in the Post-War World." From 1939 to 1943, Wachuku was secretary of the Association of Students of African Descent (ASAD) in Ireland. 1944 saw him elected president of the ASAD. During 1945, he represented ASAD at the fifth Pan-African Congress held in Manchester, England. From 1943 to 1945, Wachuku was founder, organiser and secretary of the Dublin International Club. He was president of the club from 1945 to 1947 and resigned when he returned to Nigeria in 1947 to fight for an end to colonial rule and independence of Nigeria from Great Britain. In 1947 also, Wachuku was, for six weeks, Legal and Constitutional Adviser to the National Council of Nigeria and the Cameroons (NCNC) Pan-Nigeria Delegation that went to London to press for constitutional reforms in Nigeria. He was awarded LL.D (Honoris Causa) by Trinity College, Dublin.