S.D. Codified Laws § 13-33-10

A child may, on application of his parent or guardian, be excused from school for one hour per week for the purpose of taking and receiving religious instruction conducted by some church or association of churches. The school board shall decide at what hour pupils may be excused. No such instruction may be given in whole or in part at public expense. The school board may allow the student to accumulate up to four hours of excused leave time to be taken consecutively on any one day or two hours to be taken on any two days.