The rescue happened around 6 p.m. when a charter boat taking students on a field trip hit something submerged in the waters off Bloodsworth Island, according to ABC Baltimore affiliate WMAR.
"The children put on life jackets as the boat went down," Department of Natural Resources spokeswoman Candy Thomson told WMAR. "A nearby waterman pulled all 22 passengers onto his vessel and dropped them safely on the bank of the Honga River."
Police said the captain of the stricken boat was airlifted to Peninsula Regional Medical Center. Two others were taken to local area hospitals for treatment with unspecified injuries.
The Coast Guard is leading the investigation with assistance from Department of Natural Resources Police.