That is also something I don't know the answer to, but I know the the suitable for surfing waves found in rivers are a tidal bore or a standing wave
Competitions are usually held in the ocean. You can find one near you if you live near the ocean.
How do you define surfing? Well, it is a sport that takes place on the water's surface when a wave carries the rider toward shore How does one learn this skill? I am not sure about that, but I know that surfing is when you ride a wae with or without the use of a board Is this a difficult skill to learn? I am not sure about that also,but I know that waves in which you can surd are found primarily in the ocean, altough they can be found in rivers and lakes also Really?  That is so cool!  Where does one go to find surfing competitions?
Waves suitable for surfing are primarily found in the ocean, but can also be found in lakes or in rivers in the form of a standing wave or tidal bore.