Minoru Saito docked his yacht, the Shutendoji II in Miura, Kanagawa prefecture, late on Monday - 244 days after he left Japan for his seventh circumnavigation of the globe.
Just one day later, another Japanese adventurer, Kenichi Horie, 66, was to return to Japan after a similar voyage - his second successful solo, non-stop, around-the-world voyage.
Upon arriving, Saito joked with supporters: "I've failed! I wasn't able to break 180 days."
"To all of my supporters, thank you so much," he said on NHK public broadcaster as the crowd broke into cheers and applause.
Saito's supporters, as well as Japanese media and independent adventure websites, said the 71-year-old adventurer was the oldest to successfully complete the voyage, renewing the previous record, set by himself in 1999 when he was 65.
According to his official website, Saito's trip took him past New Zealand, around the southern tip of Chile, South Africa's Cape of Good Hope and Tasmania island in Australia on a roughly 50,000km journey.
Horie left his home port of Nishinomiya in western Japan in October and followed a similar route taken by Saito.
He achieved his first solo, non-stop, around-the-world voyage in 1974, which was the westbound voyage, according to Kyodo news agency.
The latest voyage was an eastbound trip.