<jats:p>Invasions of marine species are changing coastal food webs worldwide, impacting on trophic interactions between native species (e.g. predator-prey relationships). Here, the impact of 3 macrozoobenthic invasive species on food web structure and functioning at Balgzand (western Wadden Sea) is quantified by using ecological network analysis (ENA). The bivalves <jats:italic>Ensis leei</jats:italic> and <jats:italic>Magallana gigas</jats:italic> were observed for the first time in 1984 and 2001, respectively, and the polychaete <jats:italic>Marenzelleria viridis</jats:italic> appeared in 1989. Although <jats:italic>E. leei</jats:italic> and <jats:italic>M. viridis</jats:italic> reached similar peak biomasses in the 2000s (ca. 1700 and 2000 mg C m<jats:sup>-2</jats:sup>, respectively), the bivalve consumption was higher (&gt;45% of total consumption) than that of the polychaete (&lt;10%). Biomass and impact of <jats:italic>M. gigas</jats:italic> remained relatively low. <jats:italic>E. leei</jats:italic> occupied an ecological niche that was relatively unoccupied, which led to competitive advantage with respect to other suspension feeders. Increasing biomass of <jats:italic>E. leei</jats:italic> coincided with a 70% increase of trophic carbon transfer from primary to secondary producers and an 80% increase from secondary producers to detritus. Carbon flows from secondary producers to higher trophic levels were reduced by more than 60%. These shifts in trophic transfer were stronger than those observed during the invasion of <jats:italic>M. gigas</jats:italic> in the NE Wadden Sea. At Balgzand, biomass of <jats:italic>M. gigas</jats:italic> and <jats:italic>M. viridis</jats:italic> rapidly declined to low values in the 2010s, implying a temporally limited impact. In the 2010s, <jats:italic>E. leei</jats:italic> was still responsible for 30% of the total consumption in the 2010s, indicating a longer-term impact.</jats:p>