In August 1940, the squadron was dispatched to Seletar, on Singapore, where it operated its Wirraways in support of ground forces that had been stationed there amid concerns of war with the Japanese. In early 1941, No. 21 Squadron, the squadron was re-designated a fighter unit and was sent to Sembawang to re-equip with the Brewster Buffalo. In mid-1941, as war with Japan became more likely, the squadron was sent to Malaya, operating out of Sungai Petani, where they augmented four other British Commonwealth, including No. 453 Squadron RAAF. The five British Commonwealth units—including two RAF and one Royal New Zealand Air Force squadrons—that flew Buffalos in the Malayan campaign were beset with numerous problems, including poorly built and ill-equipped planes; inadequate supplies of spare parts; inadequate numbers of support staff; airfields that were difficult to defend against air attack; lack of a clear and coherent command structure; antagonism between RAF and RAAF squadrons and personnel, and inexperienced pilots lacking appropriate training.