Taylor Royce Wood died Saturday afternoon in an accidental drowning, the Ada County Coroner's Office announced Monday.
Authorities previously said that it appeared Wood, 23, was pinned underwater after his boogie board was caught in tree branches in the Boise River near the Willow Lane Athletic Complex off State Street.
Witnesses said Wood had tied a rope from his board to a tree. He was found with the ankle strap to his board still attached to his leg.
The witnesses told emergency responders that the last time they saw Wood, he appeared to be pulling himself to shore with the rope. The witnesses said they walked away for a short time and came back to find their friend submerged in the river. It was unclear exactly how long he may have been submerged.
The friends called for help, dragged Wood to shore and began CPR. Firefighters and paramedics continued lifesaving measures, but Wood was pronounced dead shortly after arriving at Saint Alphonsus Regional Medical Center in Boise.
Boogie boarding is legal in the area where the accident occurred, Hightower said. It is prohibited only between Barber Park and the diversion dam at Ann Morrison Park.