Chuck Kunellis of Fair Oaks said it was "emotional" to read the unopened letters, which his father mailed from Italy to Arlington, Va., in 1944, but they never arrived at their intended destination for unknown reasons, KXTV, Sacramento, Calif., reported Tuesday.
The letters remained lost until John Armstrong, an Australian stamp collector, bought a collection of letters from a U.S. dealer.
"They were just a bunch of letters. And when I was sorting through them, I found these two that didn't look like they'd been opened," Armstrong said.
Armstrong researched the sender, Chris Kunellis, and found his son, Chuck. The two exchanged emails and Armstrong sent the letters to Kunellis.
"So, I posted it to him because that's where they belong," Armstrong said. "They're only about 70 years late, which is quite something really, if you think of it."
Kenellis said the letters brought back memories of his parents, who have both died.
"It was a bit emotional. I felt like a child again," Kunellis said.
Armstrong said it was not unusual for letters sent from Italy during World War II to become lost.
"It was quite chaotic. The fact that any man got any mail was quite astonishing," he said.