How long can submarines stay underwater?

Submarines can stay underwater for extended periods, often ranging from several days to weeks, depending on their type and technology. Nuclear-powered submarines can remain submerged for months at a time, limited primarily by food supplies and crew endurance. Conventional diesel-electric submarines typically have shorter underwater endurance, often around a week, due to the need to surface for air or recharge batteries. Advances in technology continue to enhance the underwater capabilities of submarines.