Sunset sails are very popular in Waikiki. It is just amazing sailing off the coast of waikiki. There are also not overally expensive. Sunset sails tend to be open bar all you can drink, day sails are cheaper and buy your dringks. This is real sailing so it can get really bumby for the sea sick type. You push off the beach so do not wear a long dress because you will walk thru a little water. I recommend the maitai, very nice boat, good seating, sails smooth and they take online reservations. You need to book about 1-2 weeks in advance for the sunset sail. They also have a fireworks sail on Friday. website is leahi.com. They leave in front of the sheraton. Justin Bieber took a trip once
There is also the Na Hoku II which is the most popular and more of the booze cruise. Popular with the locals. Cash only and you need to reserve on the beach the day or day before nahokuii.com
They have a new boat that I have not been on called the Holokai, looks nice
If you walking thru waves is not your thing you can take the Makani from the nearby marina, they tend to have groupons. This is the boat the priates stole on Hawaii 5-0 but they gave it back
And if you have kids do not forget the pirate boat, its a blast Hawaiipirateship.com. Looks like the black pearl
On all sails day sails are cheaper and better for families
I should also mention dinner sails, but they are overpriced and not as much fun. You will never find a waikiki regular recommend one