Here are the best ballet-flat options with real arch support (good for long days, plantar‑fasciitis, or people who just want more comfort) — focused on styles you can buy in/ship to Australia. I list what makes each one supportive, who it’s best for, and where to buy locally or online.

Top picks

1. Vionic (Orinda / Skimmers styles)

• Why: Podiatrist-designed footbeds with built‑in arch support, removable orthotic insoles and available widths; widely recommended by podiatrists and shopping editors as one of the most supportive ballet‑style flats. (prevention.com)
• Best for: people who need true structural arch support and prefer a classic, polished flat.
• Where to buy in Australia: Vionic has AU retailers and often appears on Amazon AU and international sites that ship to Australia.

2. Arcopedico L14 (and other L‑series)

• Why: Specifically marketed in Australia with a dual arch support system, an anatomic cushioned footbed, removable insole, flexible washable construction — popular for foot conditions (plantar fasciitis, bunions). Available from the Arcopedico Australia store. (Arcopedico.com.au)
• Best for: travel, those who want washable, lightweight flats with medium arch support.

3. Clarks supportive flats (e.g., Rena / Daiss / other cushioned styles)

• Why: Clarks often includes cushioned footbeds, contoured support and Ortholite or specialized insoles in many flats. Editors frequently recommend Clarks as supportive everyday flats. (elle.com)
• Best for: walking days / commuters who want a balance of style and cushioning.
• Where to buy: Clarks Australia stores and online.

4. Margaux The Demi (and similar Margaux flats)

• Why: Plush cushioned footbed (multi‑layer foam) and slightly shaped insole gives more arch comfort than typical fashion flats — recommended by style editors for comfort plus dressier looks. (purewow.com)
• Best for: dressier outfits where you still want extra cushioning and multiple width options.
• Where to buy: Margaux ships internationally (check shipping to Australia) and some stockists may carry them locally.

5. Söfft Kenni (Söfft supportive flats)

• Why: Leather-lined footbed with high‑rebound foam and a supportive insole; reviewers and editors call them an “orthopedic all‑star” among ballet flats. (purewow.com)
• Best for: people who prefer leather flats with cushioned arch support and a slightly scrunch‑back heel for fit.

6. Rothy’s The Flat (with removable insole option)

• Why: Sustainable knit flats praised for comfort and fit; note they are lightweight and often need an added supportive insole for strong arch support — but they accept a removable insole replacement. Good if you want a comfortable, washable knit and plan to swap to a supportive orthotic. (purewow.com)
• Best for: eco‑minded buyers who don’t require heavy structural arch support or who will use a custom/aftermarket orthotic.

7. Budget / temporary options — Dr. Scholl’s flats and Afeetsing (Amazon)

• Why: Dr. Scholl’s and some mass-market brands make flats with gel or contoured insoles that add arch cushioning at a lower price; some Amazon brands (Afeetsing) are noted by reviewers for cushioned arch support. These can be a good short‑term solution or tryout before investing in pricier supportive flats. (prevention.com)
• Best for: trying out arched flats on a budget.

How to choose the right one (quick checklist)

• Look for built‑in contoured footbeds, a defined arch in the midsole, and a heel cup — these three elements make the support meaningful. (prevention.com)
• Removable insoles are useful if you want to use custom orthotics or swap to a stronger over‑the‑counter arch insert.
• Try sizes with your usual socks/hosiery; some knit flats (Rothy’s) run small or snug and some leather styles recommend half size up.
• If you have plantar fasciitis or need medical orthotics, consider buying flats that accept removable insoles or consult a podiatrist for a custom orthotic to insert into the flat.

Where to shop in Australia

• Arcopedico Australia (local stock and pricing) — great for purpose‑built supportive flats. (Arcopedico.com.au)
• Clarks Australia (supportive everyday styles).
• Major online retailers (Amazon AU, The Iconic, Myer, David Jones) often stock Vionic, Clarks, Söfft and similar brands — check product descriptions for “contoured footbed,” “orthotic,” or “removable insole.”
• If ordering from international sites (Vionic, Margaux, Rothy’s), check shipping and return policy to Australia and factor in any duties.

If you want, I can:

• Compare 3 specific models (price, comfort features, Australian availability) side‑by‑side.
• Find current prices and local Australian retailers for any one of the models above.