Sorry, I meant foreign service. From what I can remember you had to have a bachelor’s and they actually preferred a master’s or even a doctorate.
https://study.com/articles/How_to_Become_a_Foreign_Service_Officer.html
Actually, having a degree isn’t a specific requirement to become a foreign service officer. State Department leaves that door open. It’s statistically unlikely that someone would become a foreign service officer without one though.
https://careers.state.gov/work/foreign-service/officer/test-process/