Garrett McNamara will surf the wake of the catamarans that cross the Tagus River in Lisbon, Portugal, on April 28, 2014.
The Hawaiian big wave rider was invited to surf the "Gasoline" river wave, an artificial ride created by modern full-throttle catamarans that connect Lisbon and Barreiro.
The "Gasoline" surf spot is only available six days per month, depending on the schedule of the big boat, the tide, and the moon phase.
It offers a two-foot wave that can be ridden for up to 150 meters.
Garrett Mcnamara will also participate in a documentary about his relationship with the Portuguese coastline.
The record for the world's largest wave ever ridden by a surfer still stands in Praia do Norte, Nazaré.
Discover how to surf the wake of a sternwheel steamboat, and take a look at the best river waves in the world.