Werner Kühnis threw the bottle into the waters of the Rhine three decades ago, along with a request for any prospective recipient to send the letter back to him.
Last week, the letter was finally returned after the bottle was discovered by a woman in Cape Town, South Africa.
"When I saw the envelope, I thought it was an ad for a lottery," Werner Kühnis told newspaper 20 Minuten.
After reading the letter, he learned that the woman had found the bottle on a beach in Cape Town.
Since she did not speak German, she sent the note on to a friend, who in turn returned it to Kühnis. The delighted auothor of the 30-year-old letter still lives in the same village, Oberriet, in eastern Switzerland.
According to the German oceanographer Volker Strass, it is unlikely that the bottle "sailed" alone to South Africa.
It may have been transported by fishermen, or by a whale, he said.
If the bottle had made it to Cape Town with external help, it would likely have crossed the Atlantic several times, said Strass, until the currents eventually brought it all the way down to Africa.
"I find it very surprising that it was even able to cross Lake Constance and the Rhine Falls," he told the paper.
Werner Kühnis said he now intened to contact the woman in Cape Town to find out more about the reappearance of his bottled message.