- Onchidoris muricata
- Onchidoris pusilla
- Onchidoris sparsa
- Ondina diaphana
- Ondina divisa
- Onoba aculea
- Onoba semicostata
- Osilinus lineatus
- Ostrea edulis
- Otina ovata
- Ovatella denticulata
- Ovatella myosotis
- Palliolum furtivum
- Palliolum striatum
- Palliolum tigerinum
- Pandora albida
- Pandora pinna
- Panomya arctica
- Paphia aurea
- Paphia rhomboides
- Parvicardium exiguum
- Parvicardium minimum
- Parvicardium ovale
- Parvicardium scabrum
- Patella intermedia
- Patella ulyssiponensis
- Patella vulgata
- Pecten maximus
- Pelseneeria minor
- Petricola pholadiformis
- Pharus legumen
- Phaseolus guilonardi
- Phaxas pellucidus
- Philine angulata
- Philine aperta
- Philine catena
- Philine pruinosa
- Philine punctata
- Philine quadrata
- Philine scabra
- Philinoglossa helgolandica
- Pholas dactylus
- Placida dendritica
- Pleurobranchus membranaceus
- Pododesmus patelliformis
- Pododesmus squama
- Polycera dubia
- Polycera faeroensis
- Polycera notha
- Polycera quadrilineata