The 5th Battalion commenced its second tour of South Vietnam in February 1969, this time under the command of Lieutenant Colonel C.N. Khan. After shaking out for two weeks, the Battalion began a reconnaissance in force in the northern and eastern parts of the rugged Nui Dinh mountain complex on 1 March 1969 – Operations Quintus Thrust I and II. Other activities followed: reacting to a significant threat against United States forces in the Long Binh and Bien Hoa areas (Operations Federal and Overlander, 10 March to 8 April 1969); ambushing in the Nui Thi Vai mountain complex (Operation Twickenham I, 2 to 13 May 1969); the Battle of Binh Ba, for which the Royal Australian Regiment received a battle honour for its action against a battalion of the 33 NVA Regiment (Operation Hammer, 6 to 8 June 1969); operations to locate and destroy the D445 Viet Cong Battalion (Operation Kingston, 14 September to 15 October 1969); and cordon and searches of the hamlets of Duc Trung, Binh Ba and Duc My (Operations Bondi I and II, 27 December to 16 February 1970).