This chapter explores opportunities and challenges in science communication ecosystems in the Caribbean islands of Aruba, Bonaire, Curaçao, Saba, Sint Maarten, and Sint Eustatius (the ABCSSS Islands), with a focus on nature conservation and mental health. Through a brief reflection on the geopolitical and historical context of the islands and its impact on science and science communication, it identifies the contemporary institutional frameworks and the colonial legacies that impact science communication in the islands. On these islands, science is often funded and guided by former colonial powers. These legacies shaped the exclusionary practices that have had a long-term impact on public engagement with science on the islands, in which ‘science is done to us instead of done with us’. This is directly related to who funds, designs, leads, executes, communicates, and benefits from scientific research and its results. Using case studies from nature conservation and mental health care communication, the chapter expands on the role local communities play in genuine engagement with research, results, and follow-up action. The in-depth analysis of the challenges in nature conservation and mental health care communication lays the groundwork for transformative practices for public engagement with science in the ABCSSS islands: (1) investing, supporting, and facilitating research and communication that is Caribbean-led; (2) recognising local knowledge and building long-term reciprocal collaborations; (3) reflecting on the dynamics of decision-making and implementing multivocality and co-creation in science communication; and (4) asking difficult questions and, in response, sometimes refusing research. These practices can transform research and communication practices and build a more embedded and community-based engagement with research in the ABCSSS islands. The chapter concludes with a reflection on the (im)possibilities of decolonising science communication and offers an alternative vision of community-based engagement with science in Aruba, Bonaire, Curaçao, Saba, Sint Eustatius, and Sint Maarten.