As a Diamond Medallion Member, you have top priority for Complimentary Upgrades for yourself and a companion to Delta Comfort+ shortly after ticketing, to First Class beginning 120 hours (5 days) prior to departure, and to the domestic Delta One® experience on the day of departure.

Diamond Medallion is the highest public tier in Delta’s SkyMiles program and offers a staggering array of elite perks. The "crown jewel" of these benefits is the Choice Benefits, where you can select items like Global Highway Upgrades (the most coveted perk), thousands of bonus miles, or gifting Gold status to a friend. Diamonds receive the highest priority for complimentary upgrades to First Class and Delta Comfort+, often clearing as early as 120 hours before departure. You also get a complimentary CLEAR Plus membership, a waiver for many baggage fees, and the highest "earn rate" for miles (11 miles per dollar spent). Additionally, you get dedicated phone support that bypasses standard wait times and "Day of Travel" assistance that is remarkably efficient during weather delays. For the frequent traveler, the combination of Lounge access (via the Executive Sky Club option in Choice Benefits) and the high upgrade probability makes the "Diamond" experience feel significantly more like private travel than standard commercial flying.