According to Jalisco state emergency officials, one of the men was swimming in the ocean at night when the crocodile attacked, and his friend went into the water to help.
The first man was bitten on his legs, arm, abdomen and chest. The second suffered a hand wound.
Both were taken to the hospital and are expected to survive. Both men are from Colorado.
Crocodiles are fairly common in that part of Mexico and there have been attacks before.