The singer has been moved from the trauma unit at Jackson Memorial Hospital into intensive care, and his condition downgraded from critical to stable.
Kingston, 21, suffered multiple injuries when the jet ski he was riding with an unnamed female friend crashed into a bridge.
His publicist, Joseph Carozza, said: 'Sean Kingston is now stabilised and has moved from the trauma unit to ICU. Sean's family thanks everyone for their prayers and support during this time.'
Coast Guard member Jonathan Rivera told TMZ that, following the accident, he held onto Kingston for about 15 minutes until a police boat arrived.
He said that the Beautiful Girls star was 'convulsing and throwing up blood', although he responded when Rivera told him he would be alright, and repeated, 'I'm going to be OK'.