S.D. Codified Laws § 3-12C-1203

For any generational member, normal retirement age is sixty-seven for Class A credited service and for Class B credited service as a justice, judge, and magistrate judge and age fifty-seven for other Class B credited service. The Legislature may increase the normal retirement age for some or all then-contributing members if life expectancy at retirement continues to increase, as substantiated by a periodic actuarial experience analysis that takes into account census data of all active members, vested terminated members, and retired members as well as beneficiaries of the system.