Guillermo Osvaldo Marro (born 1 July 1983) is an Argentine Paralympic swimmer who competes in international elite events.

He is highly regarded as Argentina's most successful Paralympic swimmer.

[1][2][3] In 2014, Marro became the first Argentine Paralympic swimmer to cross the English Channel, he completed the swimming course in over fourteen hours.

He swam as part of a team with Scott Patterson and Pedro Rangel who were double leg amputees, Moises Fuentes who is a paraplegic and Enrique Guerrero who has a below the knee amputation.

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