S.D. Codified Laws § 23-3-41

At the earliest practicable time, the commission shall provide, by regulation, that no person shall be appointed as a law enforcement officer, except on a temporary or probationary basis, unless such person has satisfactorily completed a preparatory program of law enforcement training at a school approved by the commission. No law enforcement officer who lacks the education and training qualifications required by the commission may have his temporary or probationary employment extended beyond one year by renewal of appointment or otherwise. However, in municipalities of the third class, the probationary period may be extended for one additional year.