Olympic swimming champion Michael Phelps has been given a one-year suspended sentence and 18 months probation after his arrest for driving under the influence of alcohol and speeding.

He must also continue to receive treatment for alcoholism, said judge Nathan Braverman of Maryland District Court in Phelps’s home state.

During the sentencing period, Phelps is not permitted to drink alcohol, but is allowed to leave the country to compete and train, the judge told the court on Friday.

Phelps said he had completed a rehabilitation program, and that he was looking ahead after making mistakes.

“During the 45-day program, I was able to find out a lot about myself,” he said.

Phelps is now attending Alcoholics Anonymous meetings, the court heard.

The swimmer added he was looking forward to a “much brighter future than I’ve had in the past.”

Braverman said he hoped Phelps would not repeat his behaviour, telling the swimming star: “I’m optimistic we won’t have this conversation again.”

Police say Phelps’ white Land Rover was doing 135km/h in a 70km/h zone in Baltimore’s Fort McHenry Tunnel early on the morning of September 30.

He was suspended from competition for six months after his arrest in September.

Phelps is the most decorated Olympian of all time with 18 golds out of 22 total medals.