Abstract A survey of the Leptostracan fauna of the British Isles collected from routine environmental monitoring samples revealed six species of Nebaliidae to be present in shallow waters. These species were identified as Nebalia herbstii Leach, 1814, Nebalia strausi Risso, 1826, Nebalia borealis Dahl, 1985, Nebalia kocatasi Moreira, Koçak and Katagan, 2007, Nebalia reboredae Moreira and Urgorri, 2009 in Moreira et al., 2009a and Sarsinebalia urgorrii Moreira, Gestoso and Troncoso, 2003. The presence of N. strausi , N. kocatasi , N. reboredae and S. urgorrii is reported from the British Isles for the first time. Three further species have been previously reported from the waters surrounding Britain and Ireland but were not recorded in the current study. Thus, the number of species recorded in the British Isles now stands at nine and the range of several species is extended northwards from previous records in the Mediterranean and the Iberian Peninsula. The diagnostic characters of Sarsinebalia Dahl, 1985 are discussed and it is suggested that a formal reappraisal of the genus be conducted. A key to European Leptostraca is provided based on adult females.