Carly Warson (10E) and her longtime friend, Stephanie Korn (10DD) don't mind sharing their bust size with the public.

After all, if not for their openness, and frustration when shopping for swimwear, they may never have launched their own label, which targets women with narrow backs and larger breasts.

"Finding bathers was impossible," recalls Warson. "I'd buy a [size] 16 and get the back taken in and throw the bottoms out."

Frustrated by the wastage and lack of choice, the women spent three years researching their brand, The Fold, which launched this year.

Offering tops exclusively in a D cup and up, The Fold is one of several new Australian niche swimwear labels that are disrupting the industry which for decades was dominated by a handful of players.

As department stores and mass-market brands flounder, niche retail is prospering – just look at the booming athleisure market, including names such as P.E. Nation and Nimble Activewear, as proof.

Patreece Botheras launched Duskii four years ago "because there was nobody doing active swim for people over the age of 20".

"We are niche but we are growing. You can buy a Duskii, you can be on a beach and be unique ... they are individual pieces. It's not the same tops that have been going for 20 years. We are mixing it up and changing the shapes according to what women want."

Duskii has experienced double-digit growth in the past year, spurred in part by its success on social media – Michelle Bridges is a fan – as well as support from major stockists, including The Iconic.

The e-tailer has more than 60 swimwear brands on its books and counts both niche labels and household names, such as Seafolly and Speedo, among its best sellers.

While there is a shortage of official data on the size of the swimwear industry in Australia, Seafolly claims it has between 20 per cent and 30 per cent market share.

But that didn't deter Taryn McLean from taking on the industry giants with her eco-swim label, Lou Lou St Cruz.

"I didn't want to stay in the fashion industry any longer knowing what it was doing to our planet. It was giving me no joy," she said.

A trained international textiles buyer and couturier, McLean set about finding an ecologically-friendly fabric she could use to make swimwear using the skills and precision she once brought to red carpet and bridal gowns.

Using a fabric made from recycled fishing nets, McLean's swimwear is eco first – it's fully recyclable – but still has a strong fashion and performance functionality.

"There's companies using 50+ SPF but doing a simple triangle. What's that going to do? Cover your nipples?" she said.

In a similar vein, Warson and Korn started The Fold out of their own frustrations with a legacy industry that hadn't evolved with women's bodies, and Australian beach culture.

"It didn't come from rational thinking," says Korn. "It came from feeling under-catered for and struggling. It was an emotional start to the business."