#### Abstract

(…)The occurrence of solitary dolphins (i.e., those in isolation from conspecifics) is well-documented in the case of bottlenose dolphins (Tursiops truncatus) along the western seaboard of northern Europe (Lockyer, 1990); however, cases of solitary common dolphins are more unusual (Vella, 2005; Genov et al., 2012). This may be due to their offshore distribution which makes longitudinal studies of individuals (e.g., by photo-identification) more difficult. Common dolphins are known to range over large distances – for example, 400 km in 5 d (Zagzebski et al., 2006) and, in exceptional cases, a minimum of 1,000 km in just under 2 y (Genov et al., 2012). Herein, an unusual case of an individual common dolphin associating with a harbour porpoise in a semi-enclosed fjordic system is reported. (…)