As you can imagine, there are a number of competing companies eager to take you out to the Barrier Reef, and the choice you make is ultimately based on how much you wish to pay and whether you are expecting to relax or have a deep sea adventure. I had been eager for some time to go SCUBA diving on the Great Barrier Reef - one of those things people are keen to tell you to do before you die - so I chose a company called Great Adventures which had come highly recommended. It seems that, while some other companies will just take eager new divers out on a boat and encourage them to sit on the edge of a platform at the back and roll off - which in my mind requires a certain degree of guts - Great Adventures actually has their own pontoon set up for people more interested in the experience than the daring.

Our boat left Cairns at 8.30 this morning and headed out to Green Island, another of the multitude of National Parks off the coast of Northern Queensland. Whereas some companies specialise in taking everyone straight out into the middle of the reef, kitting them out with diving equipment and chucking them over the side, Great Adventures goes for an all-round approach and base themselves from a sort of self-contained entertainment resort and spa off the coast. Once on Green Island, we had two hours to enjoy the facilities - these included a perfect white sandy beach for sunbathing, two large oceanside swimming pools where old ladies seemed to be doing aerobics in the shallow end, a rainforest walk and a marine park which I could wander around at my leisure whilst keeping a careful eye on the Crocodiles. There were also bars and cafes and plenty to keep people amused should they decide to stay on the island and not go on to the reef later in the day.

Those of us who had been looking forward to the opportunity to SCUBA dive the Great Barrier Reef for some time were provided with a long questionnaire to fill out before arriving on the island. This wanted to know complete details of my medical history, whether I thought I might be pregnant, if there was any history of insanity in the family and generally whether there was any chance of me suddenly pulling my mask off underwater or eating the fish. I found this questionnaire only slightly less patronising than the one they give you on planes that wants to know if you intend to commit any acts of terrorism whilst in the country, but I patiently ticked all the "No" boxes nonetheless and everything was fine. After arrival on Green Island and while everybody else was relaxing by the pool, us divers in training were given a complete briefing which involved a one-on-one talk with an instructor to make absolutely sure I wasn't a raving lunatic, a question and answer session to make sure it had all sunk in, and half an hour of diving in the pool wearing an oxygen mask and sounding like Darth Vader. At times it felt as though I was back at school doing a test, but I kept my cool and told myself that the end result would be something I'd be able to tell my kids about in years to come - especially as Great Adventures provides a video of the dive which I can force them to watch again and again until they agree to do their homework.

After the briefing, there was a cooling off period where it was suggested we walk around and make absolutely sure in our heads that SCUBA diving was for us - no doubt some people are put off slightly by the revelation that holding your breath while wearing the SCUBA equipment is likely to collapse your lungs or cause an embolism, as does coming up or going down too quickly and seemingly many other things. I told myself that I was going to do this dive whatever happened, and if I was actually alive at the end of it then that would just be a bonus.

Great Adventures have a pontoon permanently moored in the middle of the reef and after getting back on the boat at mid-day, it took us about an hour to get to it. The options once there didn't seem to be any narrower than on Green Island - there was a sunbathing deck, steps into the water for snorkelling, a platform from which we would be starting our dive later, a miniature submarine on which we could explore the reef in comfort, and a landing pad for the helicopter which will show you the reef from the air.

Those who went snorkelling were warned to stay close to the pontoon and to look up occasionally and wave - it appears that there is a real problem with older visitors going out to snorkel, laying down in the water and then turning out to be dead when the time comes for them to come in! Needless to say, many of the activities are optional extras for which large wallets are required. My main criticism of the day, though, was the fact that there just wasn't enough time - even though it would cost an arm and a leg, you really need to do two separate day trips to the reef to enjoy everything they have on offer. Because of the times at which the submarine and helicopter were scheduled to go, there was simply no way of going SCUBA diving and still taking part in either of these activities, which frankly was something of a large disappointment and meant that my only option was to roast on the sundeck until the instructor called us for the dive.

I looked particularly strange kitted out in my wet suit, snorkel, fins and breathing tank. The wetsuit took forever to get on and refused to zip up, and the tank weighed an absolute ton - but I was assured that as soon as we were in the water the weight would simply disappear. There was a cameraman going on the dive with us to film for those of us who had paid extra for a video, and he took great pleasure in capturing many extended scenes of us waddling around on the pontoon balancing on one foot and trying to get our equipment on - this reminded me somewhat of the cameramen on BBC nature documentaries who stand happily by and watch cute little fluffy tiger cubs being torn to shreds by crocodiles in the name of watchable television without actually thinking to wade in and do anything to help. At various points, usually just when I was about to fall over or topple off the side of the pontoon on one leg, the cameraman would suddenly appear out of nowhere and stick a microphone in my face, presumably expecting some sort of spontaneous and witty comment - I usually told him to spontaneously and wittily stick his mic where the sun don't shine! I had also had the foresight to bring along a disposable underwater camera too, so between us there was no way I wasn't coming away with something to remember the experience by.

Finally, our instructor helped me to my feet with what felt like a ton of bricks strapped to my back, and I tottered unsteadily over to the diving platform where steps led down into the water. Lowering myself into the water holding onto a safety line, it really did feel as though the weight had been lifted from my back - the tank, being full of air, wanted to float and so I found myself quite buoyant. During our briefing on Green Island, we had been taught various hand signals to be used underwater and the instructor ran through them once more before we finally dipped our heads under, linked arms and kicked off towards the reef. Every now and then, our guide would swim around in front of us and indicate that he wanted to know if we were alright, which got slightly irritating as we were far more interested in gaping at the multicoloured fish all around - it was also very confusing as the thumbs-up hand gesture generally used in everyday life to indicate "I'm fine" actually means "Help me, I'm drowning. Please pull me quickly up to the surface." when SCUBA diving! We were expected to check our oxygen meter regularly and also had a depth indicator as we had been told to hold our noses and blow hard to prevent ear pain every ten metres further down we went. We were also instructed that we could clear any water out of our masks by pulling them slightly away from our faces and pressing a purge button - but if they seriously thought I was going to even consider taking my mask off underwater, even just a little bit, they obviously didn't know me very well! I'm not sure how deep we actually got to, but I didn't experience any problems with my ears and probably would've been far more interested in what I was seeing to notice even if I had.

To the fish, we were clearly just other big fish. As soon as we headed for the seabed, we were immediately surrounded by multicoloured sea creatures of every description, some of which didn't look remotely like anything I've seen in my life. They weaved in and out of my legs, flicked past my nose, came up and had a good look through my goggles to see if there was anything interesting in there. Every piece of coral we passed was filled with brightly coloured fish, darting in and out and occasionally poking one eye out as we passed to make sure we weren't a shark. One fish, affectionately known as Wally the Wrasse, is probably the size of two average people and is so curious of these strange two legged creatures exploring his domain that he follows everyone around and has the fish equivalent of a good sniff until he gets bored. Of course, you're not allowed to just go around touching fish and running your hands all over the reef as this is a protected environment and it's just these sorts of things which will erode it away to nothing - but there are places where the guides will allow the group to settle onto the seabed and feel a particular well-stroked piece of coral. The fish, of course, are quite difficult not to touch as there's so many of them it's difficult not to brush several thousand of them as you swim.

One thing nobody tells you about, and you don't expect, is the sudden rush of noise when you surface. For half an hour, you've been underwater in almost total silence with water in your ears clogging up your hearing anyway - when you suddenly get your head above water again in the middle of a group of a hundred people having fun and shouting and asking how it was, it's as though somebody has stuck a trombone in your ear and is playing Waltzing Mathilda at three thousand decibels.

The cameraman was better behaved underwater, getting us together in groups for photos and swimming around looking for good angles. The end result is a video which looks very professionally put together - it begins with a really long advert for the company, but since that advert consists of some of the best underwater reef footage they've collected over the years this isn't really something to be bothered about. The second half of the video covers our dive, including some of the more embarrassing comments made while we were all being interviewed beforehand(cough) and the whole of our dive experience from start to finish - most holiday videos are something you watch once and then put away to show the grandkids one day if they've done something to upset you, but this is a film I'm likely to want to watch again and again.

About Simon and Burfords Travels:

Simon Burford is a UK based travel writer. He will be re-publishing his travel blogs, chapters from his books and other miscellaneous rantings on these pages over the coming weeks and months, and the entry on this page may not necessarily reflect todays date.