An Adelaide man will face separate drink driving charges after going to a police station to ask for directions.

The 27-year-old was breath-tested at the police station, charged with drink driving and had his licence cancelled on the spot.

Police say the man went to the Aldinga station, south of Adelaide, on Friday to ask for directions to a local school so he could pick up his grandchildren.

After being charged, the man left the Aldinga police station - and drove away.

Patrols later found him driving again, with his grandchildren in the car.

The man is due to face court next month.