Disney ships dock at the island, making the visit an uncomplicated project for the hundreds of families with small children who disembark for a day of sun and fun.
It's also important for multigenerational groups, said Randy Garfield, president of Walt Disney Travel Co. and executive vice president of worldwide sales and travel operations for Disney Destinations.
"The extended families who sail with us often have little kids and grandparents, so we decided early on that we would build the dock and avoid tenders altogether," he said in a recent interview aboard the Disney Fantasy.
"That's very unusual for a private island call," he added. "And we did a lot of environmental work before we constructed the dock."
My Disney Fantasy preview cruise in late March offered a full-day call at Castaway Cay, giving me plenty of time to explore the activities, beaches, shops and lunch venues. Disney makes it easy to get around by providing open-air trams and four tram stations. (Click here or on the photos for a slideshow of photos from the preview cruise
They operate across the attraction areas on a timely rotation, which means passengers never have to wait more than a few minutes to hop on board or hop off at their chosen destination.
A waterview walking path is available for those who want to get some exercise.
On my visit, I used the walking path from the dock and meandered around the family beach and restaurant areas, then hopped a tram to get to the more remote Serenity Bay, an adults-only beach. Even that was a short ride, maybe three minutes.
There are attractions on Castaway Cay for every age group.
Scuttler's Cove is for young children, as is the family beach area with its very popular Pelican Plunge water slide.
The Hideout is for teens. Sports areas offer volleyball, soccer and tetherball, and In-Da-Shade Games features billiards and Ping-Pong, among other options.
Castaway Ray's Stingray Adventure provides an interactive stingray experience, and boats and snorkeling equipment can be rented. Bicycles are available for rental, and there's a circular bike path through the island's shady foliage.
Serenity Bay is reserved for those 18 and older; it's a gorgeous stretch of white-sand beach with its own restaurant and plenty of lounge chairs. Covered cabanas are available for those who prefer to stay out of the sun.
Massage Cabanas also are available to the adult crowd.
Six eateries on the island offer covered or outdoor seating and dish up fare such as salads, pastas, corn on the cob, barbecued chicken and ribs, burgers and hot dogs. There's no charge for food.
The Conched Out Bar, Sand Bar and Castaway Air Bar serve a variety of frozen drinks, cocktails and beer, and passengers use their ship identification card to pay for what they order.
It's a fun atmosphere, with strategically placed items all tying into the castaway theme, including a wrecked vintage airplane peeking out from some trees. At Mount Rustmore, old buoys bear the faces of Mickey Mouse, Pluto, Donald Duck and Goofy.
The children who I saw exploring the island seemed so excited by the variety of activities and places to go that they hardly knew what to do first. It was a hot and sunny day, and many of them headed first to the family beach for a dip in the water and a ride down the water slide.
Castaway Cay even has its own post office, where passengers can drop a letter or postcard that will have a Castaway Cay postmark on it.
The 4,000-passenger Disney Fantasy sails alternating seven-day Eastern and Western Caribbean cruises from Port Canaveral, Fla. Every sailing calls at Castaway Cay. For cruise news and updates, follow Donna Tunney on Twitter @dttravelweekly.
Aside from the sheer beauty of Castaway Cay, Disney Cruise Line's private island in the Bahamas, and its slew of attractions, there's also a major convenience factor: no tendering.