A univoltine species; early June to mid August (Else & Edwards, 2018; Stanisavljevic, 2000)
Parasites and predators Coelioxys conoidea is a well known cleptoparasite of this species both in Britain and on the continent. A large form of C. mandibularis may be an additional cleptoparasite in West and Mid Glamorgan (Hallett, 1928) and Merseyside, but this requires confirmation based on individuals reared from known Megachile maritima nests.
In Ireland, several female C. elongata were observed inspecting M. maritima nest entrances at The Raven, County Wexford, in July 1999 (S.P.M. Roberts, pers. comm.).