Like that first glimpse of the Pyramids or the Great Wall of China, few travellers forget their very first dive on the Great Barrier Reef. One minute you are pulling on fins and adjusting your mask, the next you are enveloped in a wonderous, silent, zen-like world of multi-hued coral and schools of darting tropical fish. 

Each year, thousands of people explore this astonishing natural landmark – which covers an area greater than the UK, the Netherlands and Switzerland combined – by boat, helicopter, seaplane and, for a lucky few, at the helm of their own luxury yacht.

With its flawless beaches, bustling coastal towns, lush national parks and seductive island resorts, the Great Barrier Reef is impressive from just about every angle. But the real story begins just below the waves – whether you are snorkelling close to shore or venturing to the outer reefs as part of a multi-day liveaboard scuba adventure.

While some of the most celebrated dive sites require a lengthy boat trip, there are plenty of excellent places closer to the mainland, such as Green Island (near Cairns) and Magnetic Island (near Townsville) where you can encounter sea turtles, rays, giant clams and flotillas of angelfish, damselfish, coral cod and, of course, the occasional Nemo (clown fish).