The increasing rate of marine invasions to Western Europe in recent decades highlights the importance of addressing the central questions of invasion biology: what allows an invader to be successful, and which species are likely to become invasive? Consensus is currently lacking regarding the key traits that determine invasiveness in marine species and the extent to which invasive and indigenous species differ in their trait compositions. This limits the ability to predict invasive potential. Here we propose a method based on trait profiles which can be used to predict non-indigenous species likely to cause the greatest impact and native species with a tendency for invasion. We compiled a database of 12 key biological and life history traits of 85 non-indigenous and 302 native marine invertebrate species from Western Europe. Using multivariate methods, we demonstrate that biological traits were able to discriminate between native and non-indigenous species with an accuracy of 78%. The main discriminant traits included body size, lifespan, fecundity, offspring protection, burrowing depth and, to a lesser extent, pelagic stage duration. Analysis revealed that the typical non-indigenous marine invertebrate is a mid-sized, long-lived, highly fecund suspension feeder which either broods its offspring or has a pelagic stage duration of 1–30 days, and is either attached-sessile or burrows to a depth of 5 cm. Biological traits were also able to predict native species classed as “potentially invasive” with an accuracy of 78%. Targeted surveillance and proactive management of invasive species requires accurate predictions of which species are likely to become invasive in the future. Our findings add to the growing evidence that non-indigenous species possess a greater affinity for certain traits. These traits are typically present in the profile of “potentially invasive” native species.