I’ve been snorkeling a few times before, but they were all boat rides out to deeper water. Hanauma Bay was a singular experience.
On the plus side, there are no boat rides or $100 operator fees. Pay just $5 to get into the Nature Preserve, set up your spot, and go swimming as much or as little as you want, in water as deep or as shallow as you want. And the water is as clear as any off-beach water I’ve seen.
There are some downsides, but not due to the preserve itself. You have to get yourself to Hanauma Bay, either with a rental car, or a $40 taxi ride. No operator means your beach responsibilities are your own. Pack your own food, bring your own equipment, and watch over your own things; things do get stolen. The public nature of the beach means that it can get extremely crowded, both on the beach and in the water. I’m not that strong a swimmer so I stayed in the shallower water. There was no lack of fish in the shallow water, but the floating sediment did contribute to slightly decreased visibility.
Based on advice we had read elsewhere, we got up at the crack of dawn to arrive at Hanauma Bay when it opened at 6am. We got to make first tracks on the beach, and had the bay pretty much to ourselves for a few hours.
The first tour buses started arriving around 9am, and it got unpleasantly crowded very quickly after that. People were standing on the reef (a big no-no, since it kills the coral), kicking each other in the water out of either clumsiness or disregard, and also disrupting underwater visibility from kicking up sand.
We were very glad we arrived as early as we did, and left soon after the buses came. We were a little worried about being able to get a ride back to Waikiki since we had arrived by taxi, but that turned out to be no problem. There is a municipal bus stop at the Bay as a last resort, but there are so many tour van operators coming in that it was just a matter of time before one of them asked us where we were going, and offered to take us into Waikiki for $5/head (sweet!).
If I get to do it over again, I’ll try to schedule a trip for early-morning high tide. The reef being very close to shore makes it difficult to get out to see the rest of the preserve; going at high tide would enable one to swim over the reef.