Buying a train ticket at the Madrid-Barajas Airport (MAD) is a straightforward process, provided you head to Terminal 4, where the "Aeropuerto T4" rail station is located. If you land at Terminals 1, 2, or 3, you must first take the free green shuttle bus to T4. Once there, you will find a bank of automated Renfe ticket machines (often marked with a red logo and a "C" for Cercanías). These machines have a multi-language option (including English) and accept both credit cards and cash. For a trip into central Madrid (Atocha or Chamartín), you will buy a Cercanías C1 or C10 ticket, which costs around €2.60 to €3.10. A "pro-tip" for 2026: if you have a ticket for a long-distance AVE or Iryo high-speed train, your airport transfer is usually free through the "Combinado Cercanías" program; you simply enter your 5-digit ticket code into the machine to receive a complimentary local pass. You can also bypass the machines entirely by using the "Renfe Cercanías" mobile app or by tapping your contactless credit card at the turnstiles in some sections of the station.