Strel was born in the town of Mokronog, in the Slovenian region of Lower Carniola, then part of the Socialist Federal Republic of Yugoslavia. Strel's first two river swims were the Krka river in his homeland, in 28 hours in 1992, and the boundary Kolpa river, in 16 hours in 1993. In 2000, he swam the Danube River and achieved the world long distance swimming record in 58 days. In July 2001, he achieved one more world record — of non-stop swimming in Danube within 84 hours and 10 minutes. He lost 40 pounds of weight. In 2002, he swam the entire Mississippi River in 68 days. In 2003, he swam the ArgentineParaná River. On 10 June 2004, Martin started swimming down the Yangtze River in China. He reached Shanghai in 40 days on 30 July 2004, one day before planned. Strel swam the Amazon River, commencing on 1 February 2007, finishing 66 days later on April 7, 2007. This was a record-breaking distance of, longer than the width of the Atlantic Ocean. He had escort boats that were prepared to pour blood into the river to distract meat-eating fish such as piranhas. In 2007, the Nile had been proposed as his next river, but Strel said, "I am not going to do the Nile. It's long but not challenging enough, it is just a small creek. The Amazon is much more mighty." He plans to swim across Lake Arenal on September 29, 2010 as part of his visit to an environmentalist international film festival in Costa Rica. He plans to swim about 6 kilometres from shore and then back to his starting point. In June 2011 Strel completed his Colorado River Swim challenge for the documentary Stan Lee's Superhumans More about the swim can be found at: .
''Big River Man''
Strel was the subject and star of a feature documentary entitled Big River Man directed by the acclaimed art-house director John Maringouin. The film, which won a Best Cinematography prize at the 2009 Sundance Film Festival, was critically praised for its extraordinary blend of comedy and drama. The film chronicled Strel's 3,300 mile historic swim of the Amazon River.
''Strel Swimming Adventures''
In 2010, Martin Strel and his son Borut Strel founded a company that offers in the Mediterranean and at Lake Powell, Arizona. They currently offer swimming adventure holiday tours at Lake Powell, Arizona, in Slovenia, on Croatia's Dalmatian coast swimming from island to island, in Montenegro exploring Adriatic fjords and coves, and cruising Mediterranean Turkey. Strel takes part in some trips.
