Terminal one is known as the Interisland Terminal'' and opened in 1993. It serves Hawaiian Airlines and has 13 gates, so it's for domestic flights; Gates consists of A13-A20 and B1-B5. After years of delay, soon, it will have a new six-lane TSA security checkpoint.
Terminal 2 is known as the overseas terminal'', and it opened in 1962 (August 22). It's mostly used by international airlines, such as AirAsia X, Air Canada, All Nippon Airways, American Airlines, Asiana Airlines, China Airlines, China Eastern Airlines, Air China, Air New Zealand, Alaska Airlines, Delta Air Lines, Fiji Airways, Hawaiian Airlines (Japan flights), Japan Airlines, Philippine Airlines, Qantas, Southwest Airlines, Sun Country Airlines, Jetstar Airways, Jin Air, Korean Air, United Airlines, and WestJet.
Terminal two covers C to G areas. It has 29 gates. That being said, no gate belongs to any airline, and it can change daily, depending on the needs.
The third terminal of Daniel K. Inouye International Airport is often known as the commuter terminal'', and it's a brand new branch since it opened in 2018 (May 29). It has only one gate, gate H1, and it houses Mokulele Airlines.