三藩市灣（英文：San Francisco Bay）係美國加利福尼亞州中部嘅河口灣，喺薩克拉門託河下游出海口。呢個海灣呈南北向嘅長形，周圍分佈好多城市，最主要嘅譬如舊金山、東灣嘅奧克蘭同南灣嘅聖荷西。灣入邊有4個主要島嶼。天使島係州立公園。阿拉米達係城市。金銀島原先係海軍設施，而今轉為民用。阿爾卡特拉斯島有一個監獄，20世紀嗰時𢬿來關押最惡劣嘅罪犯。呢個監獄號稱冇人走得甩，因為四面環水，水溫極低，而且有白鯊出沒。而今監獄已停用，
San Francisco Bay is an estuarine bay in central California, United States, at the mouth of the lower Sacramento River. The bay is long in a north-south direction and is surrounded by cities such as San Francisco, Oakland in the East Bay, and San Jose in the South Bay. There are 4 main islands in the bay. Angel Island is a state park. Alameda is the city. Treasure Island was originally a naval installation, but now it is used for civilian use. There is a prison on the island of Alcatraz where the worst criminals were brought in in the 20th century. The prison claims that no one can escape because it is surrounded by water, the water temperature is extremely low, and white sharks are infested. Now that the prison is out of service,