PFDs must be worn by passengers on a vessel that is operating at speed higher than slow-no-wake-speed.
Boat Length
Vessels of all lengths should comply with the specified laws on wearing of PFDs.
Compulsory PFD Requirements for South Dakota
Children under seven years should always be in a USCG-approved life jacket when in a vessel operating at greater than slow-no-wake-speed.
Exceptions from wearing PFDs in South Dakota
When a child is below deck or riding in an enclosed cabin, they are exempt from wearing a PFD.
Disclaimer: The information presented here is meant to be a general reference for educational purposes. Please check with your state for the most up to date information and any current changes in the laws. Source: BoatUS