[1] In modern history, the bay was charted during the late-eighteenth century voyage of Royal Navy Commander William Robert Broughton and the crew of HMS Providence during the eruption of nearby Mount Usu.

Its opening to the Pacific Ocean is marked by a 30.2-square-kilometer-long (11.7 sq mi) line between Hokkaido Koma-ga-take and Cape Chikiu.

[5] The bay marks a junction between the arctic sea life seen in the waters surrounding northern Hokkaido and eastern Russia and the more temperate marine ecosystem seen around the rest of Japan.

[6] Arctic rainbow smelt, the Japanese lamprey, flounder, several species of shellfish, and kelp live in the waters of Uchiura Bay.

[8] In Ainu mythology it is believed that a gigantic octopus kamuy lives in Uchiura Bay.