Crocodile chases tourist swimming in Mexico (video)

The terrifying moment a crocodile closes in on a swimming tourist in Mexico has been caught on camera.

The heartstopping footage shows a young male literally swimming for his life as a crocodile stalks him in the water at Sian Ka'an.

Other holidaymakers looked on in horror from the Boca Paila bridge, reports 9News.

As the three-metre crocodile gets closer, a quick-thinking bystander throws an object down at the animal in an attempt to deter it - and, thankfully, the move worked.

Witness Manuel Carrera captured the footage recently, and said locals know not to enter the water, but many tourists are oblivious to the danger. He posted the video on to Facebook.

Post by Manuel Carrera.

He wrote: "Unfortunately, that crocodile already associated us with food and as the video shows the boy was saved because the crocodile is well fed and chased at a pace that allowed him to reach the shore."

According to news.com.au, he went on to plead with tourists to stop feeding wild crocodiles, adding: "Something should be done now".

Sian Ka'an became a UNESCO World Heritage Site in 1987.