Thermal Underwear That Works & Wows | Warmth Without Bulk

Let’s face it—winter wear often feels like a choice between looking good and staying warm. At The Foundation, we've designed a premium range of thermal underwear that proves you can have both—uncompromising warmth and sophisticated style, all without the bulk. But what if you didn’t have to choose? That’s where our thermal underwear steps in. At The Foundation, we blend function with fashion, bringing you base layers that are sleek, warm, and stylish.

Why Regular Thermals Just Don’t Cut It

• Feather-light but fiercely warm thanks to thermal knit construction
• Seamless and sleek under clothes
• Stylish enough to be seen

You shouldn’t have to look like the Michelin Man to feel cosy.

The Foundation Difference

• Crafted from merino wool, super stretch fabric, and natural fibres
• Designed to regulate body temperature and reduce body odour
• Made for sensitive skin, using side-seam free and interlock fabrics

From running errands to tackling hiking trails or hitting the ski slopes, our thermals are durable, breathable, and built for real-life wear.

Top Picks from Our Collection

1. TBL Modal Cashmere Long Sleeve Top

Luxuriously soft and breathable, this long sleeve top from our Cashmere Thermals range offers warmth without weight. It's the perfect foundation piece for layering or wearing on its own during chilly outings.

2. EGI Viscose/ Modal Legging Black

These leggings are soft, breathable, and functionally equivalent to thermal bottoms, making them perfect for layering in cold weather.

3. EGI Modal Tank Top

Smooth, lightweight, and ultra-comfortable, this tank delivers a snug base layer with breathable softness. Great under a cardigan or blazer for a chic winter look.

How to Layer Like a Pro

1. Start with a fitted thermal crew or Lace Trim Thermal Cami
2. Add a mid-weight knit or fleece pants
3. Finish with a tailored coat

Each layer helps trap heat while maintaining breathability and comfort. Thermals should be your invisible armour—not your outerwear.

Why Our Customers Love Them

"I recently purchased the TBL Modal Cashmere thermals for myself, mum and daughter. We all love them! They are so silky and refined, warm and comfortable. The cami is long enough to tuck in so it doesn't ride up and you actually forget you're wearing it because it is such a fine fabric. The order was processed super fast and the team are so professional to deal with. Highly recommend!" — Robyn C., Google Reviewer

"Fantastic customer service and beautiful products. The thermal range kept me toasty on my trip to Melbourne. I didn’t need to pile on layers." — Anne M., Google Reviewer

"Superb quality thermals. I purchased the Lace Trim Cami and was impressed by how soft and breathable it felt all day. No itch, no bulk, just warmth." — Dana R., Google Reviewer

"Staff were knowledgeable and made the fitting process a breeze. I left with a full thermal set that fits perfectly under my workwear." — Michelle T., Google Reviewer

Shop with Confidence

We offer:

• Free delivery on orders over $150
• Easy returns (just not on briefs or shapewear unless faulty)
• Support from real humans in-store and online

Check out our return policy to see how we make shopping stress-free and customer-first.

Wrap Yourself in Warmth That Works

This winter, say goodbye to bulky layers and hello to heat you can feel, not see. The Foundation’s women's thermal underwear is proof that warmth and style can go hand-in-hand. Explore our New Arrivals and find your fit—available from WOMEN XXS–XXL, including our Plus Size Collection.

Browse the full thermal collection now →

FAQs

1. Are your thermals machine washable?
   Yes! Just follow the care tag and wash on a gentle cycle.
2. Do you stock plus sizes?
   Absolutely. We cater to all body types and sizes with our WOMEN XXS–XXL and Plus Size Collection.
3. Are these thermals breathable?
   Yes—no sweaty situations here. Our fabrics are moisture-wicking, breathable, and kind to sensitive skin.
4. Can I wear them under jeans or tight clothing?
   Definitely. They're designed to stay smooth, thanks to seamless, interlock knit and super brushed inner layers.
5. Do you ship internationally?
   Currently, we ship Australia-wide. For updates, join our newsletter.

Bonus Tip: Want more performance for extreme cold?

For those braving the chilliest days, consider these top-tier thermal options:

• Cashmere-Blend Thermals: Our Cashmere Thermals combine the luxurious softness of cashmere with the durability of modal, offering unparalleled warmth without bulk.

• Wool-Blend Thermals: Explore our Wool Thermals collection, featuring garments that naturally regulate body temperature and wick away moisture, keeping you cozy and dry.

• Silk Thermals: For a lightweight yet insulating layer, our Silk Thermals provide breathable comfort, ideal for layering under your winter wardrobe.

These selections are crafted to keep you warm and comfortable, whether you're hitting the slopes or enjoying a winter stroll.t

Proudly supporting sustainable choices with our use of recycled materials, B Corp, and climate commitment.