Graham Hughes, 33, took almost four years to tick 201 countries off his list, including all 193 members of the United Nations.
As well as destinations including Kosovo, Palestine, Taiwan, Vatican City and Western Sahara.
Hughes celebrated claiming to be the first person to have visited every sovereign nation on the globe without flying, after he crossed into the world's youngest country, South Sudan.
"I've been travelling now for 1,426 days, that's 203 weeks, almost four years," said the cowboy-hat wearing globetrotter as he quaffed warm fizzy wine in the tropical heat, soon after crossing the border from Uganda.
"I started in Uruguay on January 1, 2009, and I've been travelling pretty much non-stop since then to try and be the first person to visit every country in the world without flying, and today, I just have."
Hughes based his journey on four key rules: he could not fly, must not drive his own transport, must take "scheduled ground transport" and to qualify as a visit to a country he "must step foot on dry land."
"The main highlight...has been the reaffirmation of my faith in humanity and the fact that people I?ve met on the road have been so friendly," he said.
Hughes, who comes originally from Liverpool and who also raised money for WaterAid, a British charity that works to provide clean water, had already visited northern Sudan.
South Sudan, which won independence from Sudan in July 2011, was not a country when he started his travels.
"Most people thought that I was a bit mad, a lot of people thought it was impossible," he told AFP in Juba.
Many were concerned as to how he would visit conflict-wracked nations such as Afghanistan, Iraq or Somalia, although few border controls meant that "those were the easy countries to get to", he said.
Instead, the real challenge proved to be "those tiny island nations out in the world...the guys that turn up to the Olympics with a flag and two athletes", and where perhaps only one supply ship visits each month.
His journey included "four days crossing open ocean in a leaky wooden boat to reach Cape Verde", but he was also "imprisoned for a week in Congo and was arrested whilst attempting to sneak into Russia."
He also reports to have "tip-toed into North Korea", and in 2009 visited 133 nations, setting the Guinness World Record for the most nations visited in one year by scheduled ground transport.
His website shows photographs of Hughes in every nation, as well as images of his vast array of visas filling four passports.