Drawing on long-term ethnographic research in Indonesia, this article describes a conservation outreach project that attempts to educate and convert local people into coral protectors. Both coral and the sea-dwelling Bajau people appear to be amphibious beings, moving between a changeable land-water interface, and between different, fluidly interwoven ontological constellations. We show that the failure of conservation organizations to recognize the ontologically ambiguous nature of “coral” and “people” translates to a breakdown of outreach goals. Mobilizing the concept of amphibiousness to engage this ambiguity and fluidity, we describe the moving land-water interface as the actual living environment for both coral and people. The notion of amphibiousness, we suggest, has practical and political value, in particular for reconsidering outreach and how it may be reframed as a process involving ontological dialogue. For conservation outreach to become seaworthy, it needs to cultivate an amphibious capacity, capable of moving in-between and relating partly overflowing ways of knowing and being. Providing room for ambiguity, thinking with amphibiousness furthermore encourages suspension of the (Western) tendency to explain the Other, to fix what does not add up. As such, it is of heuristic relevance for the on-going discussions of ontological multiplicity that have proliferated at the intersection between STS and anthropology.