When was the last U.S. diesel submarine decommissioned?

The last U.S. diesel submarine to be decommissioned was in 1990. This marks a significant transition in the U.S. Navy's submarine fleet as it shifted focus from diesel-powered submarines to nuclear-powered vessels, which offer greater range and endurance. The decommissioning of the last diesel submarine also reflects changes in operational requirements and advancements in submarine technology, emphasizing the Navy's commitment to modernizing its forces to meet current and future threats. This event is a noteworthy point in naval history, representing the end of an era for diesel submarines in the U.S. fleet.