ABSTRACT. – Pressure by human activities is one of the main concerns in coastal ecosystems. Port areas harbour heavily modified benthic assemblages. However, there is scarce information about responses of diverse and patchy benthic communities in the context of marine harbour infrastructures (dykes, groins, etc.) which remain inactive after construction. We studied the benthic macrofaunal assemblages on rocky substrates (epifauna) and sandy seabeds (infauna) in a harbour of Gran Canaria (Canary Islands, NE Altantic Ocean). We found that both patches of macroalgae (hard substrata) and Cymodocea nodosa seagrass meadows (soft substrata) maintained a highly diverse macrofauna in this inactive harbour. The abundance of individuals and species richness was higher in hard bottoms than in soft bottoms. Species richness showed no consistent changes between both seabeds. However, sampling stations located at higher distances and depths from the dock were proportionally the most diverse, suggesting a distance-effect independently of port infrastructure activity.