The MARTA fare is only $2.50 one way. However, you must have a new Silver Breeze Card which costs an additional $2.00. Buying a Breeze Card in person is your best bet for same-day travel and for the duration of your stay in Atlanta. Breeze vending machines are located at all MARTA stations. The Breeze Card is a long-term use card; is durable; allows the loading and reloading of various fares; and is meant to be kept for future use and reloading. You may purchase a Limited Use paper Breeze Card for only $1.00.
MARTA trains are conveniently located near the baggage claim in both airport terminals. You do not even have to go outdoors, just take the escalator up to the trains. Take either the Red Line or the Gold Line. They depart every 15-20 minutes. Exit the train at the Peachtree Center stop (N-1 Station). Turn towards the direction of the train (north) and go up the escalator. After a few steps, there will be another escalator (a really long one). At the top, you are just 5 minutes (indoors) away from the Marriott Marquis.
Walk through the Food Court to the end, turn left and follow the signs to the Marriott Marquis. On Thursday, October 13, 2017, from 9:00 am to 3:00 pm Verger Greeting Hosts (wearing bright blue smocks with the VGEC Logo) will be stationed at critical locations to help guide you along the way. When you reach the Marriott Marquis, the VGEC Registration Desk will be immediately to your left. You will be on the Atrium Level. Take the convenient escalator down one floor to reach the Hotel Registration Desk.