At first I was a bit scared because I don't enjoy diving or snorkel or the sea in general, but my husband pushed me to do it, and I have to say I'm grateful he did. It's a really something you must do before leaving Hawaii, manta ray aren't dangerous, they're the most elegant and peaceful animals on the sea.
All the crew was very attentive and professional, charming and helpfull. The captain had a very good taste for humour.
I recommended this activity to everyone, really is marvellous an unique.
Tips:
If you are a persona inclined to have sea sickness, take a pill before for that, you may have on hour of sailing on the activity and then more time floating on water.
You really must know the basics of snorkelling, otherwise you may have to forced to view the animals from the boat.
You cannot touch the manta rays.
Crew will give you some snaks on the boat, as well as fresh water.