I did a two tank dive with local guides in June 2003. We met at an access area west of the one recommended here. The lava tubes are very interesting, but if you don't like closed in places, you would miss out. Large lobsters and sleeping green sea turtles are deep inside the tubes. I was glad I dove with professionals, because it would be really easy for me to get lost or in trouble exploring here. This was well worth the money and time I spent.