Sorry mate, I only just noticed this!
My parents have just moved up to daintree (couple of hours north of cairns) , so I'll be up that way from sorta mid dec to mid jan. In terms of freediving of charters, most of them frown on it pretty highly. It's also illegal to wear a weight belt on any snorkel charter. There are however a lot of snorkelling charter boats that go out. These cost sort of $70-$200 per person for the day, and each of them go out to different reefs. You can take your own gear out on them, but I'd be hesitant to bring along a mono or long bladed fins, because they might tell you off.
There's two charter boats that I love that really stand out. The first one of these is probably the most expensive, and it's called the 'Quicksilver'. It heads out from Cairns and port douglas daily to Agincourt reef, which is on the southern end of the ribbons (they go along the continental shelf). The water here is really clear, and you'll see a lot of fish. In terms of depth, where you jump in off the pontoon is only about 15m, and most of the reef is about 3m. The Quicksilver is pretty luxurious in terms of a snorkel charter - it goes the furthest out, you'll get an all you can eat seafood buffet for lunch, and it's a really comfy ride. Head out the back while you're on your way and check the wash from the engines... twin 3000hp jets!
The trip out to Agincourt takes maybe 2 or so hours, but inside the boat are TV's with a GPS pic of the boat overlayed on a map, its good fun to watch
The other charter boat I love is called the Compass, and it's the total opposite. It's pretty old, pretty slow, and really cheap - about $70 per person. It goes to some of the inner reefs, but usually the ones that not many other boats go to. It'll take you about 3 hours to go (and it's only about half as far!), but the reefs it goes to are amazing. The added bonus with this one is that most of the reefs it goes to have big walls and drop offs - if you're lucky, you might even get a 30m dive in there, but 20 should be easy to find.
If you're on a budget, then there's a ferry leaving from Cairns, I think it's about $20 return. It'll take you out to Fitzroy island. I haven't had a chance to dive out here yet, but I'll definitely be giving it a good workout when I'm up there. You can do all your own shore dives, and should be able to find 20m+ pretty easily, within a comfortable swim. You can also take a gun over here, but some of the area is closed to spearfishing.
that's pretty much it - in terms of exchange rate, we get about .7 euros or so to $1 australian...
www.xe.com should have more accurate numbers if you like. If you want any more information, throw me a PM or put up another post.
And most importantly - enjoy your holiday! It's one of the best places in the world
