The concept of swimming with dolphins is pretty common though I'd hardly class it as swimming 'with' them. More like trying to catch up and enjoy the experience as they swim past in their droves. We were very lucky - there must have been around 300 dolphins in the water that day but the idea you are actually communicating and being with them is a myth. These are wild dolphins. You can't touch or grab onto their fins as you see in films and it's pretty exhausting work trying to hum (as described above) while trying not to swallow too much saltwater as you do, swim in circles (to imitate their behaviour and get them to interact with you) without getting dizzy and as for taking photos - forget it!
I should have learnt by now that underwater cameras are a waste of time. Not only because of the shoddy picture quality but being able to concentrate long enough to get a decent shot. I can now unequivocially say that in this instance that was impossible. You had to keep moving or lose the dolphins/freeze in the icy waters. You couldn't aim the camera properly as the dolphins swum so close you might accidently touch one and startle it. At least Jody and I had a good laugh looking at all the random snaps I'd got. A few foggy ones of whole dolphins, plus various body parts. A stomach, head, fin, one of my blurry snorkel. At least it shows they were there. A brilliant one of the only dolphin who caught my eye and stayed long enough for me to snap it. The best photos were taken from the boat when the dolphins started showing off. Dusky Dolphins are well-known for their acrobatic prowess though no-one really knows why they like doing flips and jumps so much. A great one-off experience and hopefully the last time I will ever be seen in a wet suit.
Not done too many other big water-based activities yet except previously Tubing in Waitomo on the North Island. This consists of climbing around underground in caves wearing a wetsuit, having to wade up to your neck in freezing underground rivers then sitting on to a big, rubber inflatable tyre and floating along in the dark under a ceiling of glowing maggots. Very odd indeed.