It's sunny on the wharf in Cairns and after we sign in for a Great Barrier Reef boat tour a crew member gives us a lifebuoy to hold, asks us to smile and takes our picture.
Then we board a fast catamaran ready for a day on the outer reef with another 120 or so tourists of varying ages and from countries as far apart as Brazil, Canada, France, Korea and China.
Presumably, many had been as unsure as we were about how to choose from one of the many reef cruises available. Based on our time, experience and interest, and guided by the Cairns Visitor Centre two days earlier, we chose one from Reef Magic Cruises, a smaller local company with more than 30 years' experience.
Now we are all ready to see what we can of the World Heritage-listed Great Barrier Reef, which extends 1500km along the north-east Queensland coast. It is the world's largest coral reef ecosystem and includes more than 2900 separate coral reefs, supporting more than 1500 species of fish, dugongs, sea turtles, and over 350 species of hard coral, and other species like molluscs and sponges.
The young crew are busy, enthusiastic and professional and in the 90 minutes it takes us to reach the outer reef from Cairns, tell us about safety procedures and what we can do during the five hours we will be moored at Reef Magic's pontoon, 50km away.
They are multiskilled and include two marine biologists, diving instructors, photographers, lifeguards and linguists - they also welcome us in French and Korean. As well, they seem to turn a hand to many of the other jobs necessary for a smooth trip at sea, be it serving food and drinks, fitting wetsuits and snorkels, or cleaning.
We arrive at the pontoon (or "activity platform" as it's known) at 10.30am, and walk between it and the cat all day. It's like a tiny island. The ocean surrounds us and there are reefs, just breaking the surface. Several smaller craft are at anchor nearby. Another pontoon is in the distance.
The water is enticing, vast and a little scary. White buoys mark an ocean pool in which we can swim, with a lifeguard always watching.
Soon I am snorkelling between coral outcrops, with a green sea turtle ahead and seeing fish of blues, purples and yellows, with spots, stripes and bands of colour all swimming against a backdrop of clams, colourful coral and, at some points, the reef wall with a sharp drop to the ocean floor.
It's cold, even with a wetsuit, but it's impossible to resist staying in for too long, like an awestruck child.
Back aboard there's activity all around, such as 25-minute trips with a biologist on the semi-submersible craft and glass-bottom boat. Some people are on the sundeck, some scuba diving or snorkelling for the first time. Certified divers are out with one of the guides on one of Reef Magic's tenders. In the semi-submersible, windows in the hull reveal the underwater world. Back at the pontoon, we snorkel again. Who cares about getting cold!
All too soon the hours have gone, it's 3.30pm and time to head back. And there in the cabin, laid out on a table, are all of the photos from the day and we pore over them. How did they do it so quickly? We are happy to buy a print of us boarding this morning, lifebuoy in hand. Others choose a memory stick with their underwater shots and a compilation of the fish which live on the reef.
We're all taking our day in as we return - out on the deck, sleeping, lost in thought, storing it in our memories. Happy memories.
• The Marine World Outer Reef Cruise cost $190 per adult but was on special when we travelled and cost $160 per adult and included unlimited snorkelling, morning and afternoon tea and lunch, tours on the semi-submersible and glass-bottom vessels. Additional activities included helicopter flights from $89; scuba diving from $60 and guided snorkel tours $35. All adult prices. See reefmagiccruises.com
• The Cairns Visitor Centre is at cairnsvisitorcentre.com