Sixty teams from 30 countries are in Fiji for the Eco-Challenge Race - one of the toughest mult-sport endurance competitions in the world.
The athletes were welcomed in a traditional Fijian ceremony on Monday night.
British television producer Mark Burnett, who is producing the Eco-Challenge TV series, thanked the Fijian government for allowing the competitors to stop over at villages during the race.
Teams in the Eco-Challenge Fiji race will cross through several provinces covering 670 kilometres in two weeks.
The race was last held in Fiji in 2002.
This week's race is being hosted by British adventurer and television host Bear Gryllis.