Significant collaborations with research partners in China are seen in many Western countries. With increasing US-China geopolitical tensions, governments, research institutions, and individuals in established scientific systems are increasingly required to address a proliferating array of risks and challenges associated with collaboration with China. Academic researchers are only beginning to describe how countries are responding to the ongoing need for global scientific collaboration amidst intensifying geopolitical competition. Several studies have examined the securitization of scientific connections with China in the USA, while others have documented developments in nations such as Australia, the UK, and Sweden. However, there is limited comparative research on approaches to international science amid geopolitical tensions. This paper bridges the gap, illuminating the key dimensions of variation in country-level responses by comparing the cases of Sweden and Australia. The questions we ask are as follows: Who responds to the challenges? By what means? And to what ends are responses directed? Swedish government have been largely passive, but Swedish funding agencies have developed “responsible internationalisation” guidelines that aim to induce proactive reflection by institutions and individual researchers. Australia’s approach, by contrast, has centred on legislation, the exercise of ministerial powers, along with sector-wide enactment of expanded due diligence protocols. The comparison highlights key differences in the actors, methods and goals of responses to the intensifying geopolitics of scientific collaboration.