Laizhou Bay is the southern arm of the Bohai Sea (also known as the Bohai Gulf, or just Bo Hai), which is a large relatively shallow extension of Korea Bay (Northern Yellow Sea) behind the Liaodong Peninsula to the north, and the Shandong Peninsula to the south. Both peninsulas are roughly triangular in shape and point towards the Bohai Strait, the mouth opening out to the Yellow Sea via the southern region of Korea Bay.