Planning a trip to Hawaii in 2 years with the family. We have only been snorkeling once in Destin, Florida. We loved it have bought snorkel gear to use at our camping spot on a lake (unfortunately very poor visibility) Now debating getting scuba certified before our Hawaii trip. My kids are 12 and 15. We live in Wisconsin so all our certification dives will be freshwater. After paying the money to get to and stay in Hawaii we probably will only be able to do 1 dive (maybe 2). Is it worth it? Haven't planned specifics yet of where in Hawaii we want to go (Pearl Harbor is a must though). What are some good diving or snorkeling spots?
For just a few dives it is probably not worth it. Personally I would recommend everyone just enjoy the snorkeling.
It's possible not everyone in your family will take to diving and perhaps this trip is not the time to find out. If you think diving is something the whole family would enjoy then at some point plan a diving vacation where you can work your way into a safe enjoyable hobby. There are lots of trips you can set up where you do your book and pool learning at home and all your open water training at a dive resort.
A less expensive option while in Hawai'i would be to research a reputable dive center near where you are staying and see if they have a "Discover Scuba" class (also called a "Resort Course"). This entails a short class, a pool dive and one well supervised shallow open water dive. There is no certification offered with it but if everyone is comfortable with diving then when you get home you can research certification.