Water temp is between 75-82 degrees year-round. It’s usually coldest in spring as the ocean cools over the winter and warmest in fall as it heats over summer. When you are wet, you may get chilly onboard as the movement of the boat creates wind. Don’t forget a towel, they are quite effectively warming when wrapped around you. A rash guard is always a good idea both to protect you from the sun and from any little “stingers” in the water. If you get cold easy in the water, you can always rent a wetsuit the day before at one of the dive shops around the island, such as:

Snorkel Bob’s – https://snorkelbob.com
700 Kapahulu Ave. Honolulu, HI 96816
(808) 735-7944

Aaron’s Dive Shop – http://www.aaronsdiveshop.com
307 Hahani Street Kailua, Hawaii
(808) 262-2333