Neanthes nubila (often cited as Nereis irrorata) is distributed in the Eastern Atlantic from Sweden to Morocco and the Canary Islands, including the southern British Isles and the Mediterranean Sea. This overlaps with the distribution of the similar N. rubicunda in the Azores, Madeira, Canaries and Mediterranean, so earlier records of these species from these areas will need checking. Neanthes nubila is usually found in fragile tubes in mud, from between the tides to shallow depths. Swarming mostly takes place just above the sea bed, although low numbers of epitokes can be found at the surface or on the shore. These data may also show that more northerly populations swarm earlier in the year than more southerly ones. The species may be able to withstand low salinities.