The Fort Lauderdale-bound plane made an emergency landing Wednesday at Tampa International Airport about an hour after it left Hartsfield-Jackson Atlanta International Airport.
The flight descended 19,000 feet in less than 10 minutes, according to data from tracking website FlightRadar24.
A statement by Delta says the plane was diverted out of an abundance of caution over the "cabin pressure irregularity." It says the plane is now being evaluated by maintenance technicians.
Delta said the passengers were bused about four hours to their original destination.
In a tweet, passenger Tiffany Sawyer praised the actions of the cabin crew during the emergency, writing that they were "awesome@keeping people calm."
"Now I know the bag doesn't really inflate," she said of the oxygen mask that dropped down.
The Associated Press contributed to this report.