The weather in Hawaii is generally at its most pleasant in April, May, September and October, but if you prefer it hot and dry, the best time to cruise Hawaii is from June to August. The best times to see whales are the winter months (January through March), but you'll likely experience some rain.
Do you need a passport for Hawaii cruise?
Hawaii CruisesThere's no need for a passport when you sail on any Hawaii inter-island cruise. If the ship never sails beyond the islands of Hawaii, all you need is a government-issued photo I.D. which includes a passport or a valid driver's license with a photo.