Detectives from Operation Counteract arrested a 20-year-old man of no fixed address today and charged him with an aggravated robbery which occurred at the Seaton Post Office on 11 January this year.
Police will allege two men entered the post office and threatened staff.
Both men jumped over the counter and stole money from the cash register and then ran from the store fleeing in a stolen car which was recovered by police a short time later.
No one was injured during the robbery.
Police bail was refused and the man will appear before the Adelaide Magistrates Court at a later date.