During the 1930s and into the 1940s, the League of Coloured Peoples in London, part of the Black diaspora with links to the West Indies, included Aboriginal Australia among its global concerns. This article sets out to investigate the LCP’s efforts, through its newsletter and by direct appeals to Australian governments, to promote the rights of Indigenous Australians. It did so as one aspect of its larger agenda as a Black organisation to shape the future of the British Commonwealth and end white racism globally. This hitherto overlooked aspect of the League’s history was informed in part by its interactions with the Anti-Slavery Society and the British Commonwealth League, two networks with Australian participants based in London that are more usually associated with internationalising the Aboriginal cause in this era. At the same time as the LCP was claiming to speak for Aboriginal Australia, however, Indigenous activists were promoting their own reform agendas and actively engaging in internationalism largely from within Australia.