Hayden Drage pleaded guilty to driving while under the influence of alcohol.
Police prosecutor Sergeant Rod Murray said Drage was driving a Ford Falcon on Old Coast Road at 10.48pm on April 25 and police stopped him because of the manner of his driving.
Lawyer Brian Mahon said Drage had been at the South Mandurah Football Club and decided to get some food.
Mr Mahon said Drage could not explain why the reading was so high.
Drage was disqualified from driving for 12 months.