Back in the 60's Hawaiian water men and surfers on the South Shore of Oahu AKA “the Beach Boys of Waikiki” started stand up paddling surfing the lazy waves of Waikiki. At times they would take a camera so that they could take pictures of tourist around the island learning to surf. This is where the term "Beach Boy Surfing" originates, another name for Stand Up Paddle Surfing.
In the early 2000s Hawaiian surfers such as Dave Kalama, Brian Keaulana, Rick Thomas, Archie Kalepa and Laird Hamilton started SUP as an alternative way to train while the surf was down. As the years went on they found themselves entering events such as the Moloka'i to O'ahu Paddleboard Race and Makaha's Big Board Surfing Classic.
Now you can find Stand Up Paddle Surfers in many of the Outrigger and Paddleboard races as participants within their own division.
One difference between the modern idea of surfing and SUP is that the latter does not need a wave.
In SUP, one can paddle on the open ocean, in harbors, on lakes, rivers or any large body of water. One of the advantages of Stand Up Paddle Surfing is the angle of visibility. Because of the standing height over the water one can see both deeper into the water and further across the surface of the water, allowing better visualization of features others lower above the water may not be able to see, whether it is the marine life in the harbors, lakes and coves or the incoming swells of the ocean marching on the horizon.