I've read one too many articles about how the Great Barrier Reef is dying a little more every day. Some studies predict that 95% of the reef may be gone by 2050. So, these grim stats have spurred a new type of entry called "Take Your Kids Soon," where we'll discuss places that will be very different by the time your kids are your age. Granted, these aren't the easiest destinations to go with kids (I won't claim to have toted our child to these spots yet-- I'm pulling from my pre-TJ travel experience for now), but they will be very much worth your while. For example, the Great Barrier Reef.
Travelin' Mom and I aren't exactly marine biologists, but we do like to snorkel in any destination that affords us the opportunity. Where does the Great Barrier Reef rank on our snorkeling trips? It would be an understatement just to say it ranked first. I'd say it actually offered better scenery than all of our other snorkeling trips combined. We'd love to go again. You know, before it dies and all.
That said, getting to Australia from the U.S. is a long trip. From Los Angeles, you're looking at fourteen hours. But, if your kids are good plane travelers, good sleepers, or especially susceptible to Benadryl (No, I haven't tried it myself, but it's an intriguing idea sometimes), it's worth it, because Australia is an incredibly easy country to travel in once you get there.
In terms of visiting the reef, you have two main options. First, you can stay in a port city and take day trips (or even overnight trips) on a boat. Cairns is the most popular port city, but is somewhat touristy and overcrowded as a result. If you don't mind another 90-minute drive (Aussies claim 60 minutes, but a large chunk of it is a white-knuckle drive along a narrow hillside, which makes for gorgeous views and slower speeds), you can head north to the smaller town of Port Douglas, which has the added bonus of a tropical rainforest (their motto is "where the rainforest meets the reef"). Once in town, you'll have several activity booking kiosks at your disposal, most likely in your hotel lobby. Other port cities include Mission Beach, Townsville, Gladstone, and Bundaberg. Reef day trips are relatively inexpensive (as low as $60 AUS), allow you to visit multiple dive/snorkel spots in a single day, and are a great introduction for beginners. For a more scuba/snorkel-intensive visit, you can also book multiple-night stays on several boats.
If you want an even more unforgettable experience, you can also stay right on one of the Great Barrier Reef islands. The islands' advantage is that you can do some amazing snorkeling right off the beach nearly any time of day, tide permitting. The islands also provide boats that will take divers out or take snorkelers out a little further from shore. There's an island to suit every need, from the incredibly plush Lizard Island in the north (which doesn't even take children under 12, mind you) to the more spartan, your-clearly-here-for-the-marine-life accommodations of Lady Elliot Island in the south. Other islands residing between them both geographically and on the price scale include Heron Island, Wilson Island, and Green Island. As you might guess, the more plush your island, the more you'll be paying. For example, Lizard Island will run you about $800 AUS PER PERSON per night, while Lady Elliot Island looks like a veritable bargain at around $250 AUS per person per night (and an additional $80 AUS or so for "children", although they don't indicate the age cutoff). These rates do include all meals and your snorkeling equipment and trips. Check each island out individually for other included amenities. Like amazing sunsets viewed from near-private beaches.
One warning-- although these islands are incredibly convenient for exploring the reef, getting there is another story. For example, our trip to Lady Elliot Island (Yeah- the cheapest island. That's how we roll, at least when trying to stretch out a month-long trip) required a flight from Sydney to Brisbane, Brisbane to Bundaberg, and then a small four-seater prop plane from Bundaberg to the island. On the bright side, the Bundaberg portion of the trip afforded us great aerial views of the reef, as well as a touch of Aussie airport humor.