The second, who went in the water to help, suffered a wound to his hand.
Both men were given first aid at the scene before being transferred to a local hospital, the state civil defence office said.
Mexican authorities released photos showing the men receiving treatment on the beach.
Vice reported that the attack occurred at the Bocanegra Beach at Velas Vallarta Resort on 18 July, close to where a 10 foot long crocodile was captured and released by wildlife authorities last week.
Several crocodiles attacks have occurred near the shores of the Pacific coast resort of Puerto Vallarta in recent years.
In July last year, Californian teenager Kiana Hummel was attacked and dragged underwater by a large saltwater crocodile while vacationing at the resort, ending up in hospital after fighting it off.
Associated Press contributed to this report
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