Hello Elizabeth, I’ve never been to the Big Island but have been to Maui quite a few times. There a a lot of great shore dives on Maui, One that I did just recently is the Mala Wharf just outside of Lahaina on the north side. It is an old concrete pier that was knocked down in a storm quite a few years ago. it is an easy entry off the rocks right by a boat ramp. There is lots of structure and exciting marine life including Turtles and Sharks. Don’t miss it!