The "caballitos de Totora" have been used in peru For something like 3000 years. It's not exactly surf as we know it but the concept is pretty similar.

Wikipedia

Video

hi! not discouraging other responses, but you may be interested in a couple of old posts

• Did ancient peoples "go to the beach" as we do today?

• thread in Why was surfing seemingly the focal point of popular youth culture in early 1960s America?