A postcard sent by a boy to his grandfather addressed only to "The Washing Machine Man, Ixworth" arrived at the right address two days later.
James Tungate, 6, posted the card while on holiday in Bude, Cornwall.
His father Richard wrote on top of the postcard: "I bet the Royal Mail can't deliver this."
Two days later the card arrived at the home of Gordon Palastanga, 62, of Ixworth, Suffolk, who is known as a washing machine repair man in the area.
James also wrote on the card, which was posted first class: "Dear Granddad, we caught 57 crabs. From James."
Mr Palastanga said: "I suppose I am well-known in the West Suffolk area as I have been working in the business for 27 years.
"But it was a great achievement for the Royal Mail."