Rory O'Connor posted video on YouTube of his encounter. It was shot half a mile from shore, off Florida's Siesta Key.
O'Connor says he normally keeps a camera on him in case he catches a big one. Instead, a dog named Barney paddled up to his kayak. Barney had cuts, an injured paw and was shivering in distress.
It turns out Barney's owner, 53-year-old Donna Chen, had just been hit and killed by a suspected drunk driver while she was out walking him.
"I mean, who knows what he was thinking," O'Connor said. "He was trying to get as far away from that scene as possible I imagine."
O'Connor's sister took Barney to a vet and found a microchip which helped identify him. Barney is OK and back with the owner's family.