Three sightings of Mesoplodon beaked whales are reported from the Bay of Biscay, north-east Atlantic. All sightings comprised one or two animals, breaching repeatedly in proximity to the survey vessel, and occurred at between 2200 and 4100 m water depth. Descriptive and photographic data are compared with published accounts of Mesoplodon species in the north-east Atlantic, and the identification of the animals as True's beaked whale (Mesoplodon mirus) concurs with all observed features. Within the north-east Atlantic, True's beaked whale is the only Mesoplodon species that could produce the single, closely-spaced parallel-paired scar observed on one animal. Our observations are consistent with the first live sightings of True's beaked whale in the Bay of Biscay, and only the second documented record worldwide.