Book a family-friendly hotel; many Hawaiian hotels offer children's amenities, such as welcome bags with toys upon arrival and kiddie pools where you can relax and play with your child in shallow water, and enjoy a cocktail all at once. Check hotel websites to see what amenities are offered prior to booking your room. If the hotel doesn't seem to offer any children's amenities, it probably isn't the most ideal place to travel with a toddler.
Purchase airline tickets that work with your toddler's schedule. If your toddler naps in the early afternoon, book a flight that coincides with naptime. The flight to Hawaii from the mainland is not a short one; even from California the flight is longer than five hours, which can make a child restless, bored and uncomfortable. Even if your toddler is younger than 2, opt to purchase a separate seat for her rather than making her a lap baby; the difference between having her own seat and spending this amount of time in your lap is a big deal on a flight this long.
Pack toys, snacks and activities for your toddler to enjoy first on your flight and later at your hotel. A DVD player with his favorite DVDs, crayons, coloring books, story books and a few toys will make your trip much easier. Allow your child to help pick out which toys to bring to get him excited for the trip. In addition, make sure you pack a few healthy snacks for the plane in case your child gets hungry or fussy. Avoid giving your child snacks high in sugar before or during a flight, as this will likely cause hyperactivity and restlessness.
Choose your own seats on your flight. Depending on the airline, you can choose a row with three seats; this is ideal if your toddler is your only child. She will have her own seat in between her parents and you don't have the added stress of sharing a row with strangers whom your child might bother.
Schedule your activities around your toddler's schedule. If he falls asleep in the car and misses out on your shopping excursion in Oahu, that's fine; he can sleep in his stroller while you shop. If he falls asleep in the car on the way to dinner, that's fine too, because then you don't have to worry about him being cranky at dinner. Plan activities that are fun for him around his schedule, keeping the time difference in mind; go to the beach or zoo early in the morning after he's woken up and before his naptime.
Plan separate activities during naptime. For example, if you are looking forward to time in the spa or want to hit a few golf balls, schedule it during naptime so your spouse can spend time in the hotel room with your toddler while she naps. The next day, return the favor by staying with the toddler while your spouse enjoys some free time. Order a tropical beverage and sit on your balcony with a new book while your toddler naps; everyone wins.