Yes, in 2026, the Delta Companion Certificate (issued with the Delta SkyMiles® Platinum and Reserve American Express cards) does work for travel to Hawaii. Following a significant expansion of benefits in early 2024, these certificates are no longer limited to the 48 contiguous United States. They can now be used for round-trip travel to Hawaii, Alaska, Mexico, the Caribbean, and Central America, provided the flight originates from the United States (including Puerto Rico and the USVI). For Platinum cardholders, the certificate is valid for Main Cabin only, while Reserve cardholders can use it for First Class, Delta Comfort+, or Main Cabin. You are still responsible for paying the government-imposed taxes and fees on the companion ticket, which typically range from $22 to $80 for domestic hops and up to $250 for international routes. Availability is subject to specific "fare class" inventory (typically L, U, T, X, or V classes).