Ben Friberg, 35, arrived in Key West dehydrated and exhausted but otherwise in good shape.
Before leaving Cuba, Friberg said he was "doing this to promote peace and understanding between Cuba and the United States and to promote a healthy lifestyle."
The guitarist and band leader from Chattanooga stood on his 14-foot-long board for most of the trip, sitting only for quick snacks. The crew of the support boat that accompanied him on the journey included a medic and a navigator.
Friberg was decked out with a long-billed cap for protection from the sun, close-fitting long sleeve shirt, open fingered gloves and shorts cut off below the knee. Special socks shielded his feet.
Last year, Friberg broke the record for the longest distance stand-up paddleboard journey in 24 hours, traveling 383km on Canada's Yukon River.
Friberg is believed to be the first person to cross the entire Straits on a paddleboard.
At least two Cubans have made the trip by surfboard. In 1992, Cuban-born doctor Ernesto Barral completed the journey on a wind surfing board in 19 hours, navigating by the stars at night.
In 2011, Miami lifeguard Cynthia Aguilar made the crossing by paddleboard from 22.5km off Cuba's coast. She was unable to set off from dry land because she did not have a Cuban government visa. Unlike Friberg, Aguilar completed the crossing on her knees, using her hands to paddle.
Several swimmers have attempted the journey but only Australian Susan Maroney has succeeded, making the crossing in 1997 with the help of a shark cage.
