I haven't taken any cruises around hawaii, but I live here. I just don't see any of the cruise ships that go through here being able to get that close to see the lava flowing into the ocean, I mean you might be able to see the smoke rising from a distance, but I don't think that is what you have in mind. One main reason I would think the ships couldn't go get very close is the fact that the fumes coming from the lava hitting the water are toxic. I have seen lava flowing into the ocean over there, but it was from a helicopter tour. That would probably be your best bet. Blue Hawaiian Helicopters is the one I used, they are very well informed & professional.