The 13-year-old was swimming with her 16-year-old friend while family watched. They became caught in a strong rip current.
The 16-year-old was rescued and airlifted to the hospital. The 13-year-old never resurfaced.
It was long day for the missing teen's family and for the dozens of people searching for her.
Crews searched throughout the night, and the Coast Guard relieved them at first light Saturday with assistance from the Surfside Police Department, Brazoria County Sheriff's Office and about 100 swimmers.
They used a helicopter and boats to comb the area -- more than 36 nautical miles -- for the girl. Government vehicles also patrolled the shoreline for any sign of her.
Coast Guard officials said they spoke to the girl's family late Saturday morning and decided to suspend their search around noon, but BCSO officials kept looking.
The day ended with a lot of sadness.
Authorities said her body was found around 2:30pm. It washed up about three and a half miles south of the San Luis bridge.
"The Coast Guard would like to remind beach-goers to be safe while enjoying the holiday weekend, and to heed all posted and verbal warnings regarding beach conditions from lifeguards and other authorities," Petty Ofc. Joseph Medina, search and rescue controller at USCG Sector Houston-Galveston, said in a release Saturday.
Stay with Eyewitness News and abc13.com for more information as it becomes available.