Though we still don't have an exact date for when The Diplomat Season 3 will premiere, Netflix has complete confidence that it will be a hit, as they've already renewed the popular political thriller for another season. Debuting back in 2023, The Diplomat stars Keri Russell as Kate Wyler, the new United States ambassador to the United Kingdom who works to defuse an international crisis, forge strategic alliances and adjust to her new place in the spotlight.