A letter destined for the Australian city of Penrith ended up 10,500 miles away - landing in the UK town of Penarth instead.
Vale of Glamorgan resident Keith Georgiou received the red postal envelope and quickly realised it had been sent to the wrong address.
He told the BBC he received it last weekend, quickly noticing it was meant to go to Penrith in New South Wales - which had been abbreviated to NSW on the letter. Instead, it went to Penarth, in Wales.
"How it got to Penarth instead of Australia is a joke, isn't it," he said, adding it was not the first time he had received a letter that should have gone to Australia.
"It's just not the same address. It's sad that it's got this far.”
A Royal Mail spokesperson said mistakes sometimes happen, especially during the busy holiday season.
“We deliver up to 35 million letters a day during December and occasionally mistakes happen,” the spokesperson said.
“It appears that on this occasion a letter addressed for Penrith has been mistakenly read as Penarth … Usually, any errors made by mail sorting machines are picked up by our team, but rarely, they are not noticed in time.”
Mr Georgiou told the BBC that the letter had gone through a number of sorting offices, and even the local postman had failed to notice the sorting error.
"It's got the airmail sticker, everything correct on it, and it ends up in south Wales. It's not even gone to Penrith [in Cumbria],” he said.
Mr Georgiou has since re-posted the letter: “Hopefully it doesn't return back here!"
News of the mix up comes shortly after the UK Government approved the sale of Royal Mail’s parent company to a Czech billionaire.
The £3.6 billion takeover of Royal Mail owner International Distribution Services by billionaire Daniel Kretinsky's EP Group paves the way for the national postal service to pass into foreign ownership for the first tim
