Snorkel Heaven can be found just about 20 minutes east of Waikiki along the 72 or Kalanianaole hwy in a place they call HANAUMA BAY. To those friends in Houston drive I-10 west 1500miles to Santa Monica, hit the gas and jump Luke Duke style the 2500miles to soft land in Diamond head crater then follow above directions. HANAUMA BAY is beautiful beyond the descriptive powers of a mere mortal especially me, please see pictures. There are 10 different types of blue and at least that many shades of green. Have fun making up names for the blue hues, like royal blue, midnight blue, high beam indicator light blue, just lost 10 dollars in the sand blue, did that kid just pee on the coral blue? O.K. the last blue didn't really happen....? HANAUMA BAY opens at 6am everyday except Tuesday when it's closed so the fish can talk about us behind our backs, "Did you see what she was wearing, that suit is so fall of '04, I can't believe she wore that to see us. I mean I'm a Rainbow Parrotfish. I look good everday, but it takes work." The parking lot cost $1 per car, and tends to fill up by 9-10am, however people don't stay all day as excruciatingly painfull beauty can be quite tiring, and people are leaving park/parking spots as early as 8am. I went three days in a row, 6:30am, 8:30am, 7:00am. Admission is $5 per adult, kids under 4 free. If you arrive before 7am, both parking and admission is free. Easier to do than you think as after long flight your body is still 37 hours ahead or something (not good with math). On your first visit, you are required to watch a 9minute "Don't touch Anything" video about marine conservation, before they let you walk down the hill to the bay. Once there, you have a 2000 ft long Cresentic Beach with lifeguard shacks, information booth (put your name on a list there so on future trips you won't need to watch the video again), Snorkel Gear rental hut, and multiple bathrooms, plus a cheap tram to take you up and down the big hill. This is a great beach whether you snorkel or not. You have to snorkel though, pick any spot and dive in. There is a spot near bottom of hill called the keyhole (sandy patch surrounded 320 degrees by reef ( a great spot for the beginner). There is another area called the channel (long sandy stretch-cleared for telecom-cables) that allows you to easily swim out to the outlying reef, which is less visited and better quality. Fish I spotted include, butterfly fish, coronet fish, convict tangs, yellow tangs, multiple larger surgeon fish, moray eels, trigger fish, parrot fish, goat fish, jacks/trevallys, and many others. The water gets cloudier and visibilty diminishes as the day goes on due to all the people and sun tan oils etc. I guess. By 11am visibility was much poorer, just go down to the far end of the bay where there are much fewer people, but with a rockier entry, lots of serious Uber-Snorkelers with wetsuits and matching gloves and fins. The personnel at HANAUMA BAY are wonderful, very helpful. This is a fun activity for the whole family, my 3 yr old daughter and I made sand castles while mommy snorkeled till she could barely breathe she was so tired. I put my daughter on a special boogie board with a plastic window cut into it, and she saw lots of fish and sea urchins. Don't miss this place.
p.s. For serious snorkelers also go to Sharks Cove on North Shore, from marine wildlife perspective it is quite superior to HANAUMA BAY, a Ferrari to a corvette, but the vette is a good car too.

The bay is fantastic. We visited on July 17th, 2005. We got there about 6:30a and they didn't even have people in place to collect the fees yet. When we got down to the beach, which requires a steep downward hill walk - the place had a good number of people there but was the quietest place we found on Oahu.

The reefs are full of fish and I literally could have spent days down there. You get going and can stay looking around for hours. We got our snorkel equipment from Snorkel Bob's in HNL for $10/day for the good stuff. It worked great and was a steal to see these beautiful fish.

Even later when we were leaving there was a good number of people coming in and it wasn't crowded or loud. They limit the number, so I think it is a nice little haven from HNL.

It costs $5/person and $1 to park. Bring extra money for food or for $2/day the trolley that takes you down and up the cliff.

Haunama Bay was absolutely beautiful. The water was a bit cold at first (we went in December) but you get used to it after awhile. We got there mid day and the beach was pretty full. We snorkeled and spent a few hours there, hoping to return the next day. When we came back they were closed. Make sure you check their schedule!
The movie they make you watch is actually very informative. It was worth paying attention to.

To be honest, this was the worst snorkeling I have ever been a part of. The main problem with this location is that the reef/coral is all very very very very shallow. You cannot float on top of the water without scraping your chest, or knees on the reef. I would recommend going out on an organized catamaran day snorkeling trip to the ocean where there is less people and less chance of future pain. There is wayyyy too many people there, parking is terrible if your going to drive, and it costs $5 to go to a beach. I would greatly recommend some other form of snorkeling. Plus, its a hassle leaving your gear on shore and worrying about theft.