Although the seaports in Hyogo Ward, Kanzaki in Amagasaki City, and Sakai City attract attention in the Osaka Bay, Watanabe no tsu was continuously functioning as the seaport at the river mouth of the Yodo-gawa River through the Heian period, the Kamakura period and the Muromachi period.
大阪湾の港も兵庫区や神崎(尼崎市)、堺市が注目されるが、平安時代や鎌倉時代、室町時代の間も渡辺津がひきつづき淀川河口における港湾の機能を果たし続けていた。