The authors discuss their findings over the past 50 years on the stretch of beach between Katwijk and Noordwijk. Over the years, the findings on the beach have substantially changed. Findings of Cerastoderma edule, Mactra stultorum, Spisula subtruncata, Ensis magnus, Ensis minor, Ensis ensis and Macoma balthica have greatly reduced or even disappeared. New on the beach are Lutraria lutraria, Ensis directus and Nassarius reticulatus. Considering the pace of change, the authors expect more new species to appear.