Officials say the woman was driving on Daytona Beach Thursday night, where cars are allowed, when all of a sudden she veered into the water.
Lifeguards and beachgoers jumped into action, pulling the kids out of the van as it filled with water.
A witness told a Florida TV news station that one of the kids was screaming that their mother was trying to kill them.
The children - ages 3, 9, and 10 - are now with child protective services.
