Joint Task Force Atlantic says a distress signal came from the vessel's beacon after 4 a.m. AT. A Cormorant helicopter, a Hercules aircraft, a Coast Guard vessel and another fishing vessel in the area responded.
The conditions at sea and the reason the boat sank are not known, Lt.-Cmdr. Bruno Tremblay said.
"We're really happy that the four persons were brought ashore, and they appear to be in good condition," he said.
The fishermen were airlifted to the Charlottetown Airport and arrived there by 8 a.m. They were taken to the Queen Elizabeth Hospital in Charlottetown to be checked out.