On 7 December 1941, St. Louis was moored to the pier in Southeast Lock at the time of the Japanese attack on Pearl Harbor.
At 7:56, Japanese planes were sighted by observers on board St. Louis.
Within minutes, the ship was at general quarters, and her operable anti-aircraft guns were manned and firing on the attackers.
By 8:06, preparations for getting underway had begun.
At about 8:20, one of the cruiser's gun crews shot down its first Japanese plane.
By 9:00, two more Japanese aircraft had joined the first.
At 9:31, St. Louis moved away from the pier and headed for South Channel and the open sea.
15 minutes later, her 6 in (150 mm) guns, whose power leads had been disconnected, were in full operating order.

As the cruiser moved into the channel entrance, she became the target of a midget submarine.
The Japanese torpedoes, however, exploded on striking a shoal less than 200 yd (180 m) from the ship.
Destroyers then pounded the bottom with depth charges and St. Louis continued out to sea where she joined Detroit and Phoenix, both of which also left Pearl Harbor during the attack, and a few destroyers in the search for the Japanese fleet.
After failing to locate the Japanese strike force, the hunters returned to Pearl Harbor on 10 December.
St. Louis turned to escorting transports carrying casualties to San Francisco and troops to Hawaii.

For her success during the attack on Pearl Harbor, the ship was given the nickname "Lucky Lou."
On 7 December 1941, St. Louis was moored to the pier in Southeast Lock at the time of the Japanese attack on Pearl Harbor. At 7:56, Japanese planes were sighted by observers on board St. Louis. Within minutes, the ship was at general quarters, and her operable anti-aircraft guns were manned and firing on the attackers. By 8:06, preparations for getting underway had begun. At about 8:20, one of the cruiser's gun crews shot down its first Japanese plane. By 9:00, two more Japanese aircraft had joined the first. At 9:31, St. Louis moved away from the pier and headed for South Channel and the open sea. 15 minutes later, her 6 in (150 mm) guns, whose power leads had been disconnected, were in full operating order.
As the cruiser moved into the channel entrance, she became the target of a midget submarine. The Japanese torpedoes, however, exploded on striking a shoal less than 200 yd (180 m) from the ship. Destroyers then pounded the bottom with depth charges and St. Louis continued out to sea where she joined Detroit and Phoenix, both of which also left Pearl Harbor during the attack, and a few destroyers in the search for the Japanese fleet. After failing to locate the Japanese strike force, the hunters returned to Pearl Harbor on 10 December. St. Louis turned to escorting transports carrying casualties to San Francisco and troops to Hawaii.
For her success during the attack on Pearl Harbor, the ship was given the nickname "Lucky Lou."
USS St. Louis (CL-49)