How many sailors are on a US submarine?

Answer 1

A USN WWII Gato class sub had a complement of roughly 60 officers & men.

Modern submarines typically hold a complement of between 90 - 130 officers/crew, but that number can increase during extended deployments when the entire crew is usually aboard, which often isn't always the case due to individual crew training, leave, etc. Essentially, unless you're dead or dying, you're going to sea for extended deployments.

It is not unusual to have 150 crew/civilians aboard for certain operations, and it can get a bit cramped, especially with all of the extra food/supplies aboard.