• Girls Thermal Underwear Set Fleece Lined Long Sleeve Top & Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear Black / 3-5 Years Thermal Underwear
  • Girls Thermal Underwear Set Lined Long Sleeve Top & Long Jane Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear Thermal Underwear
  • Girls Thermal Underwear Set Fleece Lined Long Sleeve Top & Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear White / 3-5 Years Thermal Underwear
  • Girls Thermal Underwear Set Fleece Lined Long Sleeve Top & Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear Marl Grey / 3-5 Years Thermal Underwear
  • Girls Thermal Underwear Set Fleece Lined Long Sleeve Top & Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear Thermal Underwear
  • Girls Thermal Underwear Set Fleece Lined Long Sleeve Top & Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear Thermal Underwear
  • Girls Thermal Underwear Set Fleece Lined Long Sleeve Top & Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear Thermal Underwear
  • Girls Thermal Underwear Set Fleece Lined Long Sleeve Top & Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear Thermal Underwear
  • Girls Thermal Underwear Set Fleece Lined Long Sleeve Top & Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear Thermal Underwear
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Heatwave Thermalwear

Girls Thermal Underwear Set Lined Long Sleeve Top & Long Jane Bottom Kids Winter Base Layer for Cold Weather by Heatwave Thermalwear

£8.00 GBP
£8.00 GBP
Sale Sold out
Tax included. Shipping calculated at checkout.
Colour
Size

Keep her warm, comfy, and ready for every winter adventure with the Girls Thermal Underwear Set Lined Long Sleeve Top & Long Jane Bottom by Heatwave Thermalwear. This cosy kids’ winter base layer pairs a soft long-sleeve top with flexible long bottoms to deliver breathable insulation without bulk. Designed for school days, outdoor play, and bedtime, it’s a customer-favorite for dependable cold-weather comfort, superior softness, and a smooth, easy-to-layer fit.

Key Feature 1: Soft and Gentle Cotton Fabric

Description: Crafted from a premium cotton-polyester blend, this thermal set wraps delicate skin in soft-touch comfort while offering natural breathability and steady warmth. The fabric is gentle for kids prone to irritation or dryness, with a lightweight feel that won’t weigh them down.

Benefits: All-day comfort that keeps her warm, dry, and cosy—perfect for school, playdates, and relaxing at home. Breathable construction helps prevent overheating, maintaining a comfortable body temperature in changing conditions. Smooth finish sits comfortably under uniforms, sweaters, and outerwear.

Key Feature 2: Flexible, Easy-Move Fit

Description: A stretchable knit adapts to every jump, run, and rest. The non-restrictive design moves naturally with the body for active days and peaceful nights, delivering a sleek base layer that won’t bunch or feel tight.

Benefits: Ideal for layering—fits neatly under school clothes and winter gear without adding bulk. Freedom of movement for sports, outdoor fun, or bedtime comfort. Retains shape wear after wear for lasting performance.

Key Feature 3: Winter-Ready Warmth

Description: Engineered to trap body heat while allowing airflow, the insulating fabric helps balance warmth in cold weather. Whether she’s on the playground or the slopes, this set keeps her snug without the sweat.

Benefits: Reliable, cosy insulation for the coldest months. Excellent for skiing, hiking, travel, and everyday layering. Consistent warmth that supports outdoor confidence and indoor comfort.

Sizes

Available in ages 3–5, 6–8, 9–11, and 12–13 years, ensuring a secure, comfortable fit as she grows. Choose her usual size for a close, base-layer fit that’s snug yet flexible.

Colours Or Style Options

Classic Black, White, and Marl Grey—versatile shades that pair effortlessly with school uniforms, pyjamas, or winter outfits.

Care Guide

  • Machine wash at 40°C with similar colours.
  • Turn inside out to help preserve softness and shape.
  • Line dry or tumble dry on low; do not bleach.
  • Wash regularly to maintain breathability and insulating performance.

Why Choose This Product

Trusted brand: Heatwave Thermalwear is known for premium-quality base layers that blend warmth, comfort, and durability.

Everyday comfort: Soft cotton feel with a flexible fit for natural movement from classroom to playground.

Winter essential: Breathable insulation that delivers dependable warmth without bulk.

Outstanding value: A complete top-and-bottom set at a great price—perfect for daily rotation.

Customer-loved: Parents praise its softness, easy layering, and long-lasting wear.

Additional Information

Usability: Ideal under school uniforms, for outdoor play, skiing, hiking, travel, and cosy lounging. Light enough for layering, warm enough to wear on its own in mild winter weather.

Warranty and Support: Backed by our satisfaction guarantee. If you’re not completely happy, our customer support team is ready to help with returns or exchanges.

Carbon-neutral shipping on all orders
5036kg
shipping emissions removed
That's like...
20627
kilometers driven by an average gasoline-powered car
We fund innovations in...
Direct Air Capture
Bio Oil
Mineralization

Shipping

We have partnered with 20 innovative grassroot companies that we believe can help reverse climate change. We allocate a fixed margin from every sale to support fund nature-based carbon removal solutions such as reforestation and soil carbon sequestration. Fund companies such as DroneSeed, Grassroots Carbon, and Pachama.

We are committed at Sock Stack to neutralize our shipping emissions and remove carbon dioxide from the atmosphere. Learn more here.

We also work closely with Royal Mail to ensure hassle-free, on-time delivery. Generally processing times are within 1 business day*. Processing times may also be extended during holidays, launches/re-stocks, limited edition releases and promotions. We will notify you as soon as your order ships or if we foresee any issues with fulfilling your order. Read our full Shipping Policy for more information.
*Please understand that business days do not include weekends and Bank Holidays (United Kingdom).

£3.95 flat fee for all domestic within the United Kingdom (free shipping over £22), 2-4 working days.
£5.95 express fee for all domestic within the United Kingdom, 1-3 working days.

Easy returns

Not completely satisfied with your purchase? Reach out within 35 days to explore hassle-free return options. We've simplified cancelations for a full refund and additionally return requests can be made from your online account. Please review our Refund Policy for more details. Thank you for your patience and understanding as we navigate this together.

Contact

Sock Stack does not have a call centre and we're not set up to handle high volumes of phone calls.

The Sock Stack brand was built online, including our customer support. Though you may receive an automated response every once in a while, all channels are manned by human staff who are eager to help you out, quickly and efficiently.

Thank you again for visiting Sock Stack. For information on our new product launches, please follow us on Instagram & Facebook. For customer service inquiries, please send us a message on Facebook Messenger or e-mail us at sockstack@outlook.com. For order inquiries, please include your order number for faster service.

Clearpay

Clearpay makes budgeting easier, allowing you to break down your payments into four installments, due every two weeks, interest free. Head over to Sock Stack and find something you love. Then, just add to bag and simply select Clearpay as your payment method at the checkout. Enjoy your new stuff right away and pay over four installments.

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Klarna

Buy now and pay 30 days later with KLARNA payment portal. You get all the “closure” of a full upfront payment, but with the cash-flow benefits of spreading the cost. The total amount charged to your card is no greater than if you simply paid for the entire purchase up front.

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Influencers

We are a young, bold homeware brand. We’re fun, we’re social and we’re an upcoming brand that doesn’t sleep. Interested in partnering? Apply today to be part of our community.

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Our Mission

Heatwave Thermalwear® envisions becoming the most celebrated, trustworthy, and sought-after brand by offering superior, distinctive, and inexpensive thermal wear products that exceed every customer's expectations. Heatwave Thermalwear's® vision is to become a leading thermal underwear baselayer brand by delivering the most refined and high-grade products to the customers that are thoughtfully developed to withstand extremely cold conditions while offering enhanced protection and unmatched comfort.

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Function, Fit & Style

Heatwave Thermalwear® strives to provide a diverse collection of the highest quality and affordable thermal underwear to men and women. Our thermal socks, long-sleeve base layers, long johns, hats and gloves are meticulously designed to be safe, lightweight, and breathable, providing fast-wicking and added warmth. As a customer-first brand, we are committed to fostering solid and lifelong relationships with our clients and aspire to deliver exceptional quality and value in our products.