One of the most intriguing efforts to revive Greece’s maritime traditions is unfolding on the island of Chios.

Nineteen teenagers on the island have been receiving their first lessons in everything a budding seafarer will need to know: navigating by the stars, reading nautical maps, role-playing as a crew and steering vessels on state-of-the-art simulators.

The instruction takes place in a new high school — up and running since September last year — in an unassuming...