Rufino Suarez, 27, was found dead on a sandbar, not far from where he went underwater, said the Galveston County Medical Examiner.
According to Galveston County Beach Patrol, Suarez and his son were in a kayak with five other people when it overturned on the bay side of the bridge.
"At one point there were seven people in the kayak, four of them were children. Two of them had life jackets, two didn't," said Chief Peter Davis of the Galveston Beach Patrol. "When the kayak turned over, it was sort of chaos. When they got back on shore they realized one man was missing."
Suarez was found not wearing a life jacket. His 5-year-old son was also not wearing one. It's unclear if the two other adults in the kayak had on flotation devices. Of the three other children, ages nine, nine and eight, two of them were wearing life jackets.
Beach Patrol says it was a 17-year-old fisherman who rescued the 5-year-old and brought him on shore.
"We flew him by air bus to the hospital. When the helicopter arrived he was conscious and alert," said Chief Davis. He was stable, but doctors kept him overnight for observation.
People staying in vacation homes along the bay heard the sirens around 7 p.m.
"All of a sudden we started seeing fire trucks that went by in that direction," said Terry, who was grilling outside.
People who fish and kayak near the bay said there need to be more signs warning people of the strong current. Beach patrol said there are 60 warning signs in the San Luis area.
"My number one rule is, do not get in the water without a life jacket," said Steve Burchner, who runs San Luis Pass Kayak.
Burchner said he often sees people wading in the water who are not wearing life jackets.
"It's very frustrating. In the last two weeks we've had two drownings here," he said.
RELATED: 19-year-old fisherman missing in water at San Luis Pass
San Luis Pass has been noted for conditions unfriendly to swimmers. Last month, a 19-year-old fisherman went missing at the pass. His body was later found.
A GoFundMe page has been set up to help cover the funeral arrangements for Suarez.
Earlier this week, Galveston Island Beach Patrol issued a red flag warning due to the potential for strong rip currents. The patrol singled out San Luis Pass as an area to avoid.
In an average year, around four to six drownings occur in the areas patrolled by Galveston Beach Patrol. So far, four people have drowned this year. Authorities urge everyone to use caution and common sense.
WATCH: How to survive a rip current
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