Our adventure on the Great Barrier Reef started at the Cairns Dive Centre shop where we were introduced to the dive crew and given an orientation by Ned about what we'd be up to for the next three days aboard the MV Kangaroo Explorer. We set sail on a catamaran to a pontoon where day trippers go snorkelling on the reef and then were picked up by a smaller boat which conveyed us to the Kangaroo Explorer. Once on board we were shepherded onto the sun deck where we received our first dive briefing and without further ado we suited up and plunged into the sea at the dive site called East Moor.

The first dive of the trip consisted of a fairly large group of five divers plus two instructors (Lee and Murray) and mainly gave the instructors a chance to assess our individual abilities. Still, the sea was a warm 27c and crystal clear, the highlight of the dive being a turtle, clown fish swimming amongst the anemones and a huge giant clam.

An hour later we were back in the water at Brigg's Reef for our second dive. This time we caught a glimpse of a white tipped reef shark and had an encounter with a massive barracuda just under our boat which at one point looked like it might attack, if Gemma had not fended it off with her camera. As we were doing 10 dives in the space of three days we'd decided to hire an underwater camera for our trip with which we were able to take loads of pictures and video.

Our last dive of the day was a first for both of us; a night dive. We were both nervous entering the water without being able to see what creatures laid in wait for us. We need not have worried as looking back the night diving wasn't as good as our daytime dives as most of the fish are asleep at night and there isn't a great deal to see. Red bass are the most frequently spotted fish as they have learnt to follow divers and their torches around to enable them to eat small fish that the divers spot. Otherwise we saw the odd crustacean, some tiny squid, a slipper lobster, a crown of thorns starfish and a pufferfish, one of Gemma's particular favourites as they like to get close to her.

Life on the MV Kangaroo Explorer was relatively comfortable and much better than life in hostel dormitories. Any time you weren't diving you were either being fed or sleeping. There was a library (which had fantastic aircon and proved a great retreat from the Sun) and drinks were available in the evening, not that either of us partook of alcoholic drinks, being so tired after diving and had to be up at 5.30am for a morning dive a sunrise. We were lucky to have our own double room (with a waterbed) as we had booked a 4 person dormitory. The boat felt quite spacious to start with as there were never more than 30 passengers whilst its capacity is around 50.

Our second day saw us do four dives including another night dive. We also started our advanced adventurer dive course which only cost us an extra AU$50 each which was a complete bargain. The first dive of the day was a deep dive (to 30 metres) and was one for our course. We did a funny numeracy and coordination test, but didn't see a great deal on the dive. The second dive was our navigation test, the first part of which we passed after which we were turned loose without the instructor to look after us. We saw more clown fish, a fantastic moray eel and took lots of photographs and video of each other. What we didn't realize was that part of the navigation test was to get back to the back of the boat, needless to say we popped up miles away and the crew needed to send out a speed boat to pick us up. We were warned that if it happened on the next dive we would fail our course!!

The third dive of the day saw us move dive site to Milln Reef to dive the Three Sisters. These were fantastic sites and the best that we visited on our three day trip. We were unguided for this dive partly because we were doing the underwater naturalist and underwater photography elements of our course and partly because we felt comfortable diving without a guide. The objective of this dive was to photograph and identify five species of coral and five species of fish and because we'd done so much diving recently we whizzed through these elements quickly leaving us with plenty of air and therefore time play around with the video camera. Gemma was posing for the camera when she saw a white tipped reef shark resting on a patch of sand. The shark swam with is for a while, its dark silhouette cutting a fantastic shape against the light of the sand, before accelerating away, it was a fantastic experience.

Last dive of the day was a night dive and we were again followed by red bass (apparently the only fish you are allowed to deliberately hit with your torch) and saw some sleeping parrot fish and a few crabs.

Another 5.30am wakeup call and we were off again, this time fighting the current and attempting the third sister (we'd been at the first and second sisters the day before) with Lee and a couple from South Africa. This dive site was unbelievably good and the best that we encountered on the Barrier Reef. As we started our descent we caught a glimpse of 3 turtles near the surface seeking some shelter from the strong currents, what a way to start a dive! We dropped straight down to 30 metres, but this was totally unnecessary as most of the sea life was around the five metre point. That said we encountered a white tipped reef shark near the bottom which we tried to get close to and followed for a while, but this ate up our air and we had to ascend for our safety stop after only 30 minutes. During our safety stop we saw schools of fish of various types (some being hunted by barracuda) and got up close with a turtle sheltering in the rocks. The turtle was particularly exciting for Craig as he hadn't actually seen one, despite Gemma having seen some on this and previous dives.

During our break Gemma was sunbathing on the sun deck and sent Craig to the cabin to get her suntan lotion. Whilst he was below deck Gemma had one of her highlight of the trip when a two metre wide manta ray surface in front of the boat.

On our second dive of the day we decided to go around the second sister unguided. Manta ray aside, we hadn't seen a ray on our trip, happily on this dive we found a blue spotted lagoon ray which we were lucky enough to swim with for a while. Immediately after that we encountered the largest of the white tipped reef sharks that we'd seen, this one swam with us for a minute or so before circling round for another look at us. Finally on this dive we did a fantastic swim-through and saw lots of beautiful spotted sweetlips which are great fish to photograph as they look great and are still most of the time being so lazy!

Our last dive was a disaster as we descended with little visibility and a strong current that took us out into the deep ocean away from the reef. We weren't (in the absence of a guide and a compass) able to get ourselves back to the reef and even at 30 metres depth we couldn't see the ocean floor or orientate ourselves. Consequently we just surfaced, swam back to the boat and called it a day.

Without exaggeration we both had an unforgettable time of our life experience on the Great Barrier Reef. The scuba diving was out of this world and life on the boat was brilliant. It was by far the best diving either of us had ever done and it was the highlight of our round the world trip so far. After three days of almost continuous diving we were exhausted but we really didn't want to leave and can't wait to get back onto a liveaboard in the near future.