The charges include causing death by dangerous driving, causing death by careless driving, and causing serious injury by dangerous driving.
He has been released on bail under certain conditions and appeared in Swansea Crown Court. One of the victims was a 17-year-old who suffered a brain injury and a broken neck.
The court proceedings are scheduled to continue, with the next appearance set for July 1, 2024. The public gallery in the courtroom included members of the victims' families.