Subwing is a watersport in which the athlete uses a pair of swiveling flaps to change his course underwater and glide through the water like a dolphin. Norwegian Simon Sivertsen came up with the idea in 2011 when he was an 18-year-old. In a water ski event, he tied a piece of driftwood to a water- skiing rope and found that he could use it to change course while being towed underwater. A year later he produced the subwing, a pair of swiveling flaps that allow the user to glide through the water like a dolphin.

The subwing hydrodynamic wings offer users the experience of flying underwater with the flexibility of motion. The sport requires a motorboat to tow the user at fast speed.