Here, we present the first comprehensive dataset of functional traits for marine nematodes (MarNemaFunDiv). In this study, we propose 16 functional traits (life strategy, body shape, trophic group, oesophageal bulb, cuticle complexity, adhesive structures and ambulatory setae, head shape, amphid (shape and size), sensory structures (head and rest of the body), light sensing, male reproductive system (spicule, pre/postcloacal supplements and gubernaculum) and tail shape). Some of these traits were already used in marine ecology as functional categories (e.g. trophic groups, tail shapes, c-p classes) while others have never been considered before. These 16 traits were described and attributed to 86 nematode genera, representing the most abundant ones in shallow-water and deep-sea ecosystems. The matrix proposed in this study encompasses a comprehensive range of traits, enabling it to tackle a variety of ecological questions in the future.