Just returned from Crystal Harmony trans-Pacific (San Francisco to Sydney) cruise.
In addition to Hawaii, we stopped in Western Samoa. Unfortunately it was Sunday, and all shops and most businesses and museums, etc. were closed. We went snorkeling at a lovely marine preserve that is only about 1/4 mile from the cruise ship dock. 2 tala (about $1) to get in, but very limited equipment (mask and snorkel, no fins) so bring your own if you plan to snorkel. It is a large reef area that is protected by a barrier reef, and the water was about 82 degrees F. There are changing rooms, toilets, and picnic tables with shelters, and some large trees if you want shade. Some others on our trip took a bus ride and saw the Robt. Louis Stevenson museum, which opened specially for the ship.
We also stopped in New Caledonia. I could have skipped Noumea (capital) as it is industrial, and very smoggy. Really enjoyed the Isle of Pines though. Little development except a small hotel, and absolutely beautiful snorkeling with wonderful coral and fish, although colder this time of year (their late winter/early spring) than Samoa (about 74-76 degrees F.). I could easily spend several days exploring this island.
Originally we were supposed to stop in Fiji, but it was eliminated due to political situation and Isle of Pines substituted.