Miyako Bay

 
 is a bay in Iwate Prefecture, in the northern Tōhoku region of northern Japan. It is a long and narrow, roughly triangular body of water extending southwest to northeast where it opens to the Pacific Ocean. The forms its southern border and forms its southern border. This gives it an area of approximately . 
Miyako Bay is approximately long, with a width of at its mouth. The bay has an average depth of 20-40 meters, with a maximum depth of .
Economically, the shallow waters of the bay are an important fishery, with shellfish and seaweed cultivation and aquaculture benefiting from nutrients brought into the almost enclosed waters of the bay the Hei River and the effects of the offshore Kuroshio and Oyashio currents. Tourism is also economically important, as parts of the bay are within the borders of the Sanriku Fukkō National Park, including the scenic Jōdogahama coastline.
The Port of Miyako serves as the main seaport for the city of Morioka. 