We overslept a little, not a good thing as our first port of call is supposed to be a popular place. We skip breakfast and head south past Diamond Head and onto Koko Head and Hanauma Beach. Everybody mentions Hanauma Beach Have you been there yet?
largely for the snorkelling and almost as much for feeding the fish -- never a good idea.
The beach is on the inner side of what was a crater, now with one side open to the sea. 
The overfeeding of the fish has made the fish numerous, the beach even more popular and led to the general ecological devastation. They're working to improve things by proposing to limit beach users to two from ten thousand a day and currently by obliging everyone to watch a short video on the place. Amongst other things trying to impress upon people that walking on the coral is not good for it.
So, armed with cheap mask and snorkel we head down from the car park (at 10am we'd picked one of the last half dozen spaces). It's not a bad beach, pretty full and lots of snorkellers. The water is cold, though, how poeple put up with it, I don't know. Surely all sea water is about 30C? This is colder than Bronte Beach, I'm sure. It's certainly the first place for a while where once you're in you think the air is warmer than the water. I'm called out by Helen shouting Ian, Ian! Where's your wallet?
Oops. I hand it and the [car and room] keys over whilst looking cool and sophisticated.
The visibility isn't too good -- the sand is churned by snorkellers and the busy sea beyond the inner reef -- but you get a good variety of fish, some a little aggresive as they're expecting food. I can't stay for long, it's too cold and there's an oft chilly breeze off the sea too. You can just about see Witches Brew, a large baylet with tempestuous currents but not the Toilet Bowl, a bowl that fills with sea water then drains from below which has the effect of flushing, dropping four or five feet almost instantly. Access to both is fenced off, they're too dangerous, people regularly drowning in both. As I loiter, trying to dry we both get burnt slightly. D'oh! From the car park you can see Koko crater a tuff cone (see sudden explosions of ash and steam) as are most of the craters on Oahu. 
No time to rest, we head up the road, stopping quickly at some view points including over Sandy Beach, a popular and notoriously dangerous body surfing spot. As they say, the waves are big but don't look dangerous. Opposite the beach is an access road up to the botanical garden inside Koko crater. Hardly the lush greenery of some gardens but they have a nice collection of plumeria which seems to be a Hawaiian speciality. We take the long loop which wastes a good hour before we rush back to Big Surf to collect valuables from the safe before the 4pm deadline.
Pressing on we run all the way back to Diamond Head and after a confusing conversation with the pay person hand over US$5 to `hike,' or in this case follow everyone else, up to the old military observation post on the rim of the (tuff cone) crater. There's quite a good view down to Koko Head and crater and up over Waikiki/Honolulu and up to Pearl Harbor (possibly, on a good day). 
It's a fair old climb, a long meandering path followed by long dark tunnels/buildings and steep stairways but worth it.
We then retraced our route back to Sandy Beach (this time noticing the sign telling us to turn left at a key junction) and followed the road beyond and around the eastern tip and up to a lookout over a place Mark Twain described as the most beautiful on Earth. Presumably before the large housing development and dual carriageway added the modern touch. It is an impressive area, a giant volcano apparently just split in two, the one half simply falling into the sea. The result is an arc of two thousand foot sheer cliffs with classic volcanic gulley erosion of the faces overlooking a plain and the sea. It was too dark and too cold to return to the car for a picture! Like the Devil's Elbow(?) in New Zealand, the old road clearly ran around the cliff face [just below us], the new road springing from a tunnel below. Our plan to reach Sunset Beach in time for sunset was a touch in vain. Not only was it past sunset but we never managed to identify the beach in daylight. What chance now?
We stopped to fill up the car. At the pump the choice was to use a credit card, giving your five digit ZIP code as a PIN, so that's RG9..., no, or pay cash in advance to the cashier. Hmm, I want to fill it up.
You have to pay in advance.
How much?
I asked, knowing there couldn't be a sensible answer. After giving the car model, and noting that the tank was still half full, ten or fifteen dollars was the suggestion -- petrol/gasoline is US$2.00 plus a gallon on Hawaii I'll start with ten, then, please.
I then stood like a lemon for a few minutes figuring out why no petrol was issuing forth. Of course, it's obvious the base of the nozzle holder needs to be lifted up... Grrr.
An hour or so later we're back in Waikiki and the absence of any food intake today is beginning to register. For ease of access we head over the road to the Outback Steakhouse, an Australian Hard Rock Cafe with fewer pretentions but just as expensive food. They seemed very popular all the same.
Big Surf, Waikiki (just), Oahu N21.28672 W157.83966 Elev. -20m (and we're on the fourth floor too!)
Copyright 2003 Ian Fitchet. All rights reserved.