This was the most enjoyable site on Big Island that we tried, so we did this one twice. Enter through the lava "bath tub" just left of the last tree in the start of the parking lot. Swim on the surface for maybe 25-30 meters, than watch for a barrier which is very close to surface. Once you crossed it, dive. Very interesting lava/coral formations (pinnacles, tunnels, caves, walls) and plentiful wildlife. That was the only place we saw an octopus and a male Hawaiian puffer with purple/orange sides. Large schools of tangs etc. Highly recommended!