In March 1943, the first Firefly Mk Is were delivered but they did not enter operational service until July 1944 when they equipped 1770 Naval Air Squadron aboard HMS Indefatigable.
I Marts 1943 blev de første Firefly Mk.I leveret, men de kom først i operationel tjeneste i Juli 1944 ved 1770 Naval Air Squadron ombord på HMS Indefatigable.