A wayward driver who crashed his van into the drink on Roosevelt Island is under investigation to determine if he was intoxicated, police said.

The drama unfolded shortly before 2 a.m. Saturday at Main Street and East Loop Road, cops said.

The unidentified 40-year-old driver was speeding when he lost control, hit a car, then crashed through a guardrail and into the East River, an NYPD spokeswoman said.

The driver and his passenger swam to shore after the crash, cops said.

“Charges are pending against the driver,” the department spokeswoman said.

The driver was taken into custody and then transported to Mount Sinai Queens Hospital for observation, the NYPD said. His male passenger, believed to be his father, declined medical treatment.