Officers were called out to the intersection of Bay Oaks Boulevard and Clear Lake City Boulevard when someone spotted the pickup in the water around 7 a.m. Thursday.
Police believe that at about 4:30 a.m., the driver of a black Toyota Tacoma was traveling southbound, lost control of the truck and drove onto a raised concrete curb. The Toyota drove onto the median, struck a tree and continued southbound, crossing the intersection of Clear Lake City Boulevard. The truck then drove on the median, crossed the northbound lanes and ended up in the golf course pond.
Dive team officers found the body inside the vehicle at about 9:30 a.m. Police say it's possible the man suffered a medical episode leading to the crash.
The 83-year-old man's identity has not been released.