Probationary periods for federal employees typically last for one year. In less common circumstances, certain agencies and federal positions require two-year, or even three-year, probationary periods. Generally, the longer probations are reserved for law enforcement officers and certain employees at the Defense Department.

https://federalnewsnetwork.com/workforce-rightsgovernance/2025/02/what-are-the-rules-for-probationary-periods-and-federal-employees/