To check in luggage for free on Delta Air Lines in 2026, the most reliable method is holding a co-branded American Express Delta SkyMiles Credit Card (Gold, Platinum, or Reserve tiers). Cardholders and up to eight companions on the same reservation get their first standard checked bag for free. Another way is through Medallion Elite Status; even Silver Medallion members receive at least one free checked bag on domestic flights. If you don't have a card or status, you can get free bags by booking a Premium Cabin ticket, such as Delta One, First Class, or Premium Select, which usually includes at least two free bags. Active-duty U.S. military personnel also receive a generous free bag allowance. Finally, Delta occasionally offers a "20-minute bag guarantee"—if your checked bag takes longer than 20 minutes to reach the carousel after your flight arrives, you can submit a claim online to receive 2,500 SkyMiles, which effectively offsets the value of future travel even if you paid for the initial bag.