In parallel with many nations' education policies, national education policies in Australia seek to foster students' intercultural understanding. Due to Australia's location in the Asia-Pacific region, the Australian government has focused on students becoming "Asia literate" to support Australia's economic and cultural engagement with Asian countries. Drawing on Allport's optimal contact principles and key factors supporting intercultural understanding, this study examines two "sister school" cultural immersion trips in Indonesia and East Timor to explore ways in which their different approaches supported positive intergroup contact and helped foster intercultural understanding among students. Focus groups and interviews with school project teams and analysis of both researcher and teacher project field notes and documents suggested that these schools' programmes could be mapped onto Allport's contact principles in different ways. The paper concludes with promising approaches that can help to inform sister school programmes.