Since there is a great need for interdisciplinary collaboration in view of the planetary crisis of the oceans, this paper proposes a sociological reflection on naturalist marine fieldwork. Fieldwork has a long tradition in both the natural and social sciences. Although the marine natural sciences rely heavily on fieldwork, and in striking contrast to the social sciences, fieldwork is, however, rarely explored on a methodological level. This paper addresses this gap based on two studies: a flash poll on ‘what does fieldwork mean” for naturalist marine researchers, and an ethnography of a large-scale taxonomist’s expedition to study marine biodiversity. It profiles four interconnected components of marine natural scientific fieldwork: an integrative methodology, the enactment of knowledge infrastructures, the co-productive character of materialities, and in-situ places. They provide an analytical framework to re-think the potential of marine fieldwork for interdisciplinary integration, including both marine social and natural sciences.