The closest airports to Gaeta are:

• All Airports in Rome
• Capodichino Airport in Naples

From the airport you can take a train to Formia and then a bus to Gaeta.

• Autostrada del Sole (A1) – Cassino Exit.
• Direction: Formia-Gaeta

• Local buses from Formia train station to Gaeta are available every 15 minutes

• Express train Rome-Naples line. Stopping in Formia.
• Local bus services from Formia to Gaeta:
  • https://www.rome2rio.com/map/Formia-Gaeta-Station/Gaeta?route=Bus&segment=0