A continuous marine broadcast, or CMB, is a marine weather broadcasting service operated by the Canadian Coast Guard. CMBs are programmed from the various centres on the Atlantic, Pacific and Arctic coasts of Canada, as well as on the coasts of the Great Lakes. Programming is broadcast in English and French on the Atlantic Coast and along the Saint Lawrence River, and in English only on the Great Lakes, Arctic Coast and Pacific Coast. CMBs are transmitted on several frequencies: As well, on the Pacific coast, CMBs are transmitted on weather radio frequencies.