S.D. Codified Laws § 25-5-7.1
In any custody dispute between parents, the court may order joint legal custody so that both parents retain full parental rights and responsibilities with respect to their child and so that both parents must confer on, and participate in, major decisions affecting the welfare of the child. In ordering joint legal custody, the court may consider the expressed desires of the parents and may grant to one party the ultimate responsibility over specific aspects of the child's welfare or may divide those aspects between the parties based on the best interest of the child. If it appears to the court to be in the best interest of the child, the court may order, or the parties may agree, how any such responsibility shall be divided. Such areas of responsibility may include the child's primary physical residence, child care, education, extracurricular activities, medical and dental care, religious instruction, the child's use of motor vehicles, and any other responsibilities which the court finds unique to a particular family or in the best interest of the child. If the court awards joint legal custody, it may also order joint physical custody in such proportions as are in the best interests of the child, notwithstanding the objection of either parent.
SDCL 25-5-7.1