In the North Pacific, right whales occur during the summer in the Sea of Okhotsk, the southeastern Bering Sea, the Aleutian Islands, and the northern Gulf of Alaska. During the winter, they occur (or at least occurred historically) southward to the Sea of Japan [=East Sea], Taiwan Strait and the Ogasawara Gunto (Bonin Islands, Japan) in the west and to Baja California Sur (Mexico) in the east. Populations on the Asian and American sides of the Pacific are regarded as discrete (Brownell et al. 2001). Vagrants have been recorded in the Hawaiian islands (Rowntree et al. 1980, Herman et al. 1980).

Formerly abundant across much of the North Pacific in summer, mainly north of 40°N, the right whale is now regularly seen only in the Okhotsk Sea and the southeastern Bering Sea, with occasional sightings along the east coast of Japan, off the Bonin Islands, and in the Gulf of Alaska. In the 1970s there were two sightings off Hawaii (Salden and Mickelson 1999) in spring and three right whales were taken in the Yellow Sea in winter (Wang 1978, 1988). Sightings off California and Mexico are rare and there is no evidence that the western coasts of the United States and Mexico were ever highly frequented habitat for this species (Brownell et al. 2001).