First-class summer is the capstone event of a cadet's training career. This is the opportunity to apply learned skills and theories, and to reinforce them through practical experience.

Cadets spend 10 weeks at sea or divide their time between five weeks at sea and five weeks in a Coast Guard internship in engineering, government, science or the operational Coast Guard.

During these shipboard assignments, cadets are treated as junior officers. Duties may include conning (navigating) the ship and running the engine room. Some cadets serve aboard Eagle as division officers, supervising the 3/c cadets. Others go to dive school or learn about operations at a Coast Guard air station.