A couple say they were "amazed" to receive a Christmas card where the only address details on the envelope were "somewhere near the sea in Suffolk".
Antony Wren, 42, from Lowestoft, Suffolk, said a former colleague had sent the card to him and his wife Sarah, but did not have their address.
The sender had written on the bottom of the envelope, posted on 6 December: "Good luck with that postie."
"It took four days to reach us... really quite impressive," Mr Wren said.
"In July 2013 we moved up to Lowestoft and sent out our new address in Christmas cards," he told the BBC.
"Obviously some of those cards must've gone missing and our friend and ex-colleague clearly has lost our new address but remembered we were moving to somewhere near the sea in Suffolk."
He tweeted Royal Mail and the Post Office to thank them for their efforts in ensuring the card was delivered.
The former colleague who sent the card had not yet been made aware they had received it, he added.