There are
344 mi
from Deerfield Beach, FL to Fernandina Beach, FL
That's the driving distance. It would take 6 hours 28 mins to go from Deerfield Beach, Florida to Fernandina Beach, Florida.
The flight distance (direct flight from Deerfield Beach, FL to Fernandina Beach, FL) is 311.82 mi.
344 mi = 552.99 kms