Customs and Immigration can take 2 1/2 to 3 hours--and the sub is not near the airport. Most folks allow 3 hrs. to get from the plane through customs. A sub tour at 2:00pm probably isn't feasible. You will need to allow time to get out of the airport and into Waikiki, which will take at least 30 min.

Clearing customs and immigration at Daniel K. Inouye International Airport (HNL) in 2026 typically takes between 45 and 90 minutes, though this can fluctuate wildly based on the number of simultaneous international arrivals (particularly the "midday rush" from Japan and Oceania). For U.S. citizens and permanent residents, the process is significantly faster if using Global Entry or the Mobile Passport Control (MPC) app, which can reduce the wait to under 20 minutes. For international visitors, the process involves fingerprinting and an interview with a CBP officer. After clearing immigration, you must collect your luggage and then pass through an Agriculture Inspection—which is uniquely strict in Hawaii to prevent the introduction of invasive species. If you are connecting to an inter-island flight (e.g., to Maui or Kauai), you should allow at least three hours for your layover to account for the walk between the International Arrivals building and the inter-island terminal gates.