The Mounties said the crash happened around 1 a.m., when a vehicle carrying four people — ages 17, 18, 19, and 20 — lost control while driving on Route 370 near Tracadie-Sheila, about 70 kilometres northeast of Miramichi.
They said vehicle slipped off the dirt road while trying to go uphill and went into the Tracadie River.
Around 3 p.m., tow trucks pulled the submerged vehicle from the river and all four bodies were discovered inside, said Cpl. Guy Paul Larocque.
Larocque said the car was in the same location where it crashed. He said officials had difficulties recovering the vehicle because of the remote location.
"It was not an easy task to pull the vehicle out," said Larocque on Saturday. "Even with a 4X4 vehicle it's difficult to access the location. The road being slippery, it was very difficult for the first responders to get to the scene."
The Mounties said the names of the victims, who are all from surrounding communities outside Tracadie-Sheila and Lameque, were not being released pending the notification of family.
Police said a crash reconstructionist is involved in the investigation.