When surfing, there is plenty of etiquette including the right of way. When there are multiple surfers in the water and heading towards the same wave, the surfer who is closest to that wave and the peak of that wave has the right of way. This means that the other surfers should not pursue surfing that wave and stay away from it and out of the line where the first surfer will be surfing said wave.
When thinking about this right of way rule in surfing, it is important to remember that surfers should not attempt late drop ins on a wave when there is another surfer already riding that wave towards the shore and getting ready to surf it. In simpler terms, don't start surfing a wave in between the whitewater of a wave and a surfer surfing that same wave. Another word for this is backpaddling.
When surfing you may come across a split peak wave from time to time. A split peak wave is when a wave has a peak that splits off into two waves, essentially, with whitewater going in two different directions (leftward and rightward). When there is a split peak wave, it is okay for two surfers to ride the same waves long as they surf in opposing directions.
When surfing, you have to paddle out to find a wave and then ride it back in. Keeping surfing etiquette in mind, it is important to paddle around and behind waves and surfers who are riding waves in.