Flat feet (also called fallen arches or overpronation) affect an estimated 20-30% of Australians. For many people, flat feet cause no problems. But for others, the collapse of the arch leads to a chain reaction of pain affecting the feet, ankles, knees, hips, and lower back.
The right insole or orthotic can correct overpronation, reduce pain, and make a real difference to how you feel after a long day on your feet. Here's what actually works, based on what we see in clinical podiatry practice.
How flat feet cause pain
When the arch collapses, the foot rolls inward (pronates) with each step. This creates abnormal stress on the plantar fascia, Achilles tendon, and tibialis posterior tendon, the structures most commonly involved in flat foot pain. Over time it also places extra load on the knees and hips.
An orthotic insole works by supporting the arch and controlling pronation, redistributing load more evenly across the foot and lower limb. The key is choosing one with enough structure to hold the arch up under your body weight. Soft gel insoles from the chemist won't cut it.
Flat feet vs fallen arches — is there a difference?
You'll see both terms used interchangeably, but there is a meaningful clinical distinction. Flat feet (pes planus) can be something you're born with — your arch simply never developed a pronounced curve. Many people with naturally flat feet have no pain at all and don't need orthotics.
Fallen arches refers to an arch that was once present but has gradually collapsed over time. This is usually caused by progressive weakening of the tibialis posterior tendon (the main tendon supporting the arch), and tends to develop in middle age, after significant weight gain, during pregnancy, or following an injury. Fallen arches are more likely to cause pain because the foot's support structures are under strain they weren't designed for.
The treatment approach is similar for both: an orthotic insole that supports the arch and controls overpronation. However, fallen arches often benefit from a firmer density orthotic because the foot is actively collapsing under load, whereas a naturally flat foot that isn't painful may only need moderate support for comfort during long days on your feet.
If your arches have noticeably flattened over the past few years, or if one foot is flatter than the other, see a podiatrist — progressive tibialis posterior tendon dysfunction responds better to early intervention than to waiting.
Best insoles and orthotics for flat feet in Australia
1. Trekker Full Length Orthotics - Best for Structured Arch Support
Trekker orthotics are our top recommendation for flat feet. The inverting heel cup, intrinsic medial skive, and navicular support directly control overpronation at its source. Unlike foam insoles that compress and lose shape, Trekker's EVA construction holds firm under sustained daily loading, which is critical for flat feet where the arch needs consistent support throughout the day.
Choose your density based on body weight:
- Trekker Full Length Firm Density - for body weight 50-80kg
- Trekker Full Length Extra Firm Density - for body weight 80kg+
- Trekker 3/4 Length Firm - for lower-volume shoes where a full-length insole won't fit
2. Formthotics Sport Run Dual - Best for Runners with Flat Feet
The Formthotics Sport Run Dual is a thermoformable foam insole that can be heat-moulded by a podiatrist to match your exact arch profile. This makes it particularly effective for flat feet as the insole conforms precisely to where your arch sits (or doesn't), providing targeted support that a generic insole can't match. The dual-density construction adds cushioning over a firmer support base.
For runners who prefer a thinner profile, the Sport Run Single offers the same mouldability in a slimmer design for tighter shoes.
3. Formthotics Everyday Workfit - Best for Work Boots
If your flat feet ache most in steel caps or safety boots, the Formthotics Everyday Workfit is designed specifically for the sustained, repetitive loading of standing and walking on hard surfaces. Dual-density foam supports the arch while cushioning against concrete and tile flooring across 10-12 hour shifts.
4. Formthotics ShockStop - Best for High-Impact Activity
The Formthotics Sport ShockStop adds a dedicated impact-absorbing layer at the heel and forefoot. Useful for heavier runners with flat feet, or anyone whose flat foot pain is worst during high-impact activity. The firmest Formthotics option with the most cushioning.
5. Powerstep ProTech Control — Best Semi-Rigid Support for Flat Feet
For flat feet that need the most structure, the Powerstep ProTech Control uses a polypropylene shell rather than foam. This semi-rigid construction provides firmer arch support than any foam insole and doesn't compress or flatten over time — a common frustration for flat-footed users who find foam orthotics "break down" after a few months. The contoured heel cradle controls rearfoot pronation, and the wide-fit option accommodates broader foot shapes that are common with flat feet. A higher price point, but the shell longevity makes it competitive over a year of use.
Choosing the right density for your body weight
One of the most common mistakes is choosing an insole that's too soft. For flat feet and overpronation, you need a firm or semi-rigid orthotic with enough structure to hold the arch up under your full body weight. A soft insole compresses under load and provides no correction.
- Under 70kg - Medium density is usually sufficient
- 70-90kg - Firm density recommended
- Over 90kg - Extra firm or dual density for adequate support
Complementary products for flat feet
- OS1st FS6 Compression Foot Sleeves - graduated compression supports the arch and reduces fatigue. Worn under socks alongside orthotics for combined support.
- Walker's Gel Plantar Fasciitis Sleeves - gel arch and heel cushioning for symptom relief when you can't wear shoes with orthotics.
- Trekker 8mm Heel Raisers - if flat feet are combined with tight calves or Achilles pain, a heel raise reduces tendon loading.
Footwear matters too
Even the best orthotic won't work well in a flat, unsupportive shoe. For flat feet, look for footwear with a firm heel counter, a slight heel raise (8-12mm drop), and enough depth to accommodate an orthotic insert. Avoid flat shoes, thongs, and minimalist footwear as these force your foot to work harder to stabilise itself and typically worsen flat foot symptoms.
Frequently asked questions about insoles for flat feet
Are orthotics good for flat feet?
Orthotics are the most effective conservative treatment for flat feet that cause pain. They work by supporting the arch mechanically — preventing it from collapsing fully with each step — and redistributing pressure away from the structures under strain (the plantar fascia, tibialis posterior tendon, and spring ligament). Not everyone with flat feet needs orthotics, but if your flat feet are causing pain in the feet, ankles, knees, or lower back, a structured orthotic can make a significant difference.
Do orthotics fix flat feet permanently?
Orthotics manage flat feet — they don't permanently change the structure. While you're wearing them, your arch is supported and your foot functions more efficiently. When you take them out, your foot returns to its natural position. Think of them like glasses for your feet: they correct the problem while in use. For children with flexible flat feet, orthotics worn during the developmental years may influence arch development, but in adults the skeletal structure is set.
What's the difference between arch support insoles and orthotics for flat feet?
Generic "arch support" insoles from supermarkets or chemists typically use soft foam or gel that compresses under body weight, providing temporary comfort but minimal structural correction. Clinical-grade orthotics for flat feet (like Trekker, Formthotics, or Powerstep) use denser materials — firm EVA, dual-density foam, or semi-rigid polypropylene — that maintain their arch profile under sustained daily loading. The difference matters most for people over 70kg, where soft insoles simply flatten out.
How do I know if my flat feet need orthotics?
Not all flat feet need treatment. You should consider orthotics if your flat feet cause pain in the feet, ankles, shins, knees, or lower back; if you notice your shoes wearing unevenly on the inside edge; if one arch is noticeably flatter than the other; or if you develop pain after increasing your activity level or time on your feet. A podiatrist can perform a biomechanical assessment to determine whether orthotics would help and which type suits your foot.
Do you need custom orthotics?
Off-the-shelf orthotics like Trekker and Formthotics work well for the majority of people with flat feet. Custom orthotics (prescribed and fitted by a podiatrist from a 3D scan or plaster cast of your foot) are recommended when off-the-shelf options haven't provided enough relief after 6-8 weeks, or when a specific structural deformity requires precise correction.
Browse our full range of plantar fasciitis products or Trekker orthotics for podiatrist-recommended insoles that work for flat feet and overpronation.
Disclaimer: This article is for general informational purposes only and does not constitute professional medical or podiatric advice. Always consult a qualified podiatrist or healthcare professional for diagnosis and treatment specific to your individual needs. If you are experiencing pain, discomfort, or other symptoms, seek professional advice before starting any treatment.