A majestic turquoise-and-gold tail splashes the surface of a public pool. Strange, beautiful creatures frolic in the water, occasionally peeking out from their masks and snorkels. Half-woman, half-fish.

Since Disney's Princess Ariel first hit the big screen over two decades ago, many little girls (and some boys) have dreamed of becoming a mermaid.

Now mermaid Crystal, as she is known, is helping turn those fantasies into reality in her swimming classes with a difference in The Netherlands.

"It's amazing," smiled a starry-eyed Marijke, 27. "It's every little girl's dream."

Marijke, Lize and Katja are among the first pupils at Crystal's Meermin School Nederland.

It is billed as the country's "first professional school" for mermaids and is only one of a handful in Europe where the phenomenon of "mermaiding" is beginning to make waves after arriving from the United States and Canada.

At the public swimming pool in the central Dutch town of Zeist, the would-be mermaids are learning to swim like Ariel, their legs firmly bound in tight material tails.

Daubed in bright aquatic prints to resemble shiny scales, the faux tails take some time to wriggle into before they can slide into the water for some intense underwater aerobics.

It's all in the technique, according to Crystal, real name Marijke Pie, who says "the movement begins from the tummy."

Her advice? Keep your feet together, don't bend the knees too much, but try to do a dolphin kick using your abdominal muscles.

Crystal usually teaches wearing just her swimsuit, preferring not to be weighed down by her 15-kilogram tail.

She bought it online, made-to-measure, from Hawaii-based Finfolk productions - where customers design their own tails - for 3,000 euros ($3,300). So great is demand that the site boasts of a waiting list of nine to 12 months.

Once in costume, a transformation takes place. Magical and mysterious, Crystal says she feels free.

"I feel more beautiful in the water. There's no stress, no pressure and I am away from all the technology. There's a real tranquility. It's incredible."

But becoming a mermaid - or a merman - takes weeks, if not months, of training.

Apprentices receive tips on everything from choosing costumes and accessories, to how to do hair and makeup so it's not ruined in the water and how to smile and keep their eyes open for underwater photos.

The final level is becoming a mermaid, and learning free-diving techniques. How to hold your breath underwater, how to blow water rings, how to protect your ears.

Crystal can now hold her breath for more than three-and-a-half minutes, and can free-dive to some 20 meters.

But if the surprised glances from other swimmers in the pool are anything to go by, it would seem the Dutch are not quite ready for mermaids.

"Oh, let them stare," said apprentice mermaid Marijke. "I'm having fun!"