Traveling from Hawaii to the U.S. mainland in 2026 involves strict USDA agricultural inspections to prevent the spread of invasive species. You are generally allowed to bring back treated flowers and leis (excluding citrus-related plants or jade vines), seashells, rocks, and sand. Fresh pineapples and treated papayas are permitted if they are properly inspected and packed. However, you are strictly prohibited from bringing back most other fresh fruits and vegetables (like mangoes, lychee, or berries), plants in soil, and certain "pest-prone" flowers like Mauna Loa. One popular "yes" item is roasted coffee, which can be brought back in unlimited quantities, but green (unroasted) coffee beans require specific inspection. All items must be declared at the USDA agricultural scanner at the Hawaii airport before you check in for your flight; failure to do so can result in on-the-spot fines of up to $1,000.