We did the Big Island when our kids were really little (1 and 5) but there were some things where I don’t think age matters:

- the volcano erupted right after our visit, but Self tour worked fine. Going at night was cool.

- I really liked the black sand beach driving south / back around the island from Volcano. It had a number of sea turtles on it.

- the Point of Refuge was interesting for something different / some history

- I’m not sure I’d recommend this otherwise, but on a rainy day we went to the sea horse farm and it was pretty interesting.

- we didn’t have a sitter so didn’t swim with the rays and we were too late to tour coffee or chocolate plantations but both sound interesting.

- the free hula show at Queen’s marketplace was fun

We stayed near Kona except for a night in Volcano. The drive to and from beaches was long - especially with traffic and construction - so I’d recommend staying further north.

And of course schedule/ pay for a luau during your trip.

Go see Pearl Harbor and at least hike diamond head or one of the waterfall areas