Top 10 Undershirt Base Layer UK – Men’s Thermal Tops

As an Amazon Associate I earn from qualifying purchases.

1. Smartwool

#ad

Smartwool Merino 250 Baselayer 1/4-Zip, Men's Deep Navy, XL

#ad
Smartwool #ad - Center back Length: medium 29in. Insulation weight: midweight 250g/m2. Style: 1/4-zip. Material: 100% merino wool. Fit: slim.
BrandSmartwool #ad
ManufacturerSmartwool #ad
Height20.32 cm (8 Inches)
Length25.4 cm (10 Inches)
Weight0.34 kg (0.75 Pounds)
Width7.62 cm (3 Inches)
Part NumberSW016355092XL
ModelSmartwool

2. 32º DEGREES

#ad

32 Degrees Men’s Heat Performance Thermal Heavyweight Baselayer Crewneck Long Sleeve Fleece Top, Stingray, S

#ad
32º DEGREES #ad - Offers full mobility and freedom of movement. Fabric: 94% polyester, 6% spandex. Perfect for everyday comfort at home and winter outdoor activities.

The thermal underwear can be worn as comfy loungewear on cold, Anti-Static, Heavyweight, Soft Fleece, chilly nights. Wash care: wash cold gentle cycle with like colors, Tumble Dry Low, Do Not Dry Clean, Non-Chlorine Bleach Only, Iron Cool if needed. Fitted: please refer to photo size chart for chest, waist, hips, and length measurements. Midweight fleece with a lot of stretch. Meant to be fitted to accommodate wearing under clothes. Soft micro-fleece on the outside, brushed for extra comfort on the inside. Features: quick dry, fitted, 4-way stretch, tag free label.
Brand32º DEGREES #ad
Manufacturer32 Degrees #ad
Weight0.21 kg (0.46 Pounds)
Part Number#4302
Model#4302

3. MERIWOOL

#ad

100% Merino Wool Midweight Long Sleeve Thermal Shirt Denim Blue, MERIWOOL Mens Base Layer

#ad
MERIWOOL #ad - Through the process of wicking, Merino wool is the most breathable fabric and absorbs moisture better than any other fibers. Wicking refers to a fabric’s ability to pull moisture away from your body and keep you comfortable. Exceptional customer care: if your meriwool men’s midweight base layer crew top doesn’t perform to your satisfaction, exchange, return it to us within 30 DAYS along with proof of purchase for a hassle-free refund, or replacement.

Wicking & odor resistance: merino wool’s natural wicking and odor-resistant properties keep you dry and comfortable while active in cold weather. Breathable: keeping you cool in summer and warm in winter, snowboarding, skiing, 250g/m2 weight interlock-knit merino wool can be used as a base layer or mid-layer, but won’t weigh you down. Includes a 90 dAY limited manufacturer’s warranty. Comfortable & convenient: quick-drying shirt features a loop for hang drying while camping, hunting, working, playing sports, hiking, or partaking in any outdoors activity.

Super soft: 100% all natural superfine 18. 5-micron merino wool ensures comfort all day – no itch! EASY CARE: Mid-weight long sleeve crew top shirt is machine-washable and dryer-safe, so it’s ready when you are for your next adventure. Package includes: 1 – merino wool men’s merino wool thermal crewneck top in denim Blue / Medium | MATERIAL: 18. 5 micron, 100% merino wool, 250g/m2 | FIT: Fitted.
BrandMERIWOOL #ad
ManufacturerMERIWOOL #ad
Part NumberMO MEN-TOPCR250-M-DNMBLU
ModelCrewneck

4. 32 Degrees

#ad

32 DEGREES Men's 2-Pack Performance Lightweight Thermal Baselayer Crewneck Top, White/Charcoal Heather, Large

#ad
32 Degrees #ad - Meant to be fitted to accommodate wearing under clothes. Lightweight knit with a lot of stretch. Fabric: 40% polyester, 34% acrylic, 22% rayon, 4% spandex.

Perfect for running, waist, hips, hiking, hunting. The acrylic blend adds additional lightweight warmth that is comfortable against the body. Wash care: wash cold gentle cycle with like colors, Do Not Dry Clean, Non-Chlorine Bleach Only, Tumble Dry Low, Iron Cool if needed. Features: lightweight, anti odor, Anti-Static, 4 Way Stretch, Moisture wicking, Tag Free Label. Fitted: please refer to photo size chart for chest, skiing, and length measurements.
Brand32 Degrees #ad
Weight0.34 kg (0.75 Pounds)
Part Number#9002
Model#9002

5. MERIWOOL

#ad

MERIWOOL Mens Base Layer 100% Merino Wool Heavyweight 400g Thermal Shirt for Men, Army Green, XXL

#ad
MERIWOOL #ad - Includes a 90 dAY limited manufacturer’s warranty. Super soft: 100% all natural superfine 18. 5-micron merino wool ensures comfort all day – no itch! EASY CARE: Heavyweight long sleeve crew top shirt is machine-washable and dryer-safe, so it’s ready when you are for your next adventure. Wicking refers to a fabric’s ability to pull moisture away from your body and keep you comfortable.

Through the process of wicking, Merino wool is the most breathable fabric and absorbs moisture better than any other fibers. Exceptional customer care: if your meriwool men’s heavyweight baselayer crew doesn’t perform to your satisfaction, return it to us within 30 DAYS along with proof of purchase for a hassle-free refund, exchange, or replacement. Package includes: 1 – men’s merino wool thermal crewneck top in army green / XX-Large | MATERIAL: 18. 5 micron, 100% merino wool, 400g/m2 | FIT: Fitted. 400g of warmth: our most popular 250g midweight crewnecks just got an upgrade! take your warmth to the next level with our new 400g heavyweight crewneck tops.

Wicking & odor resistance: merino wool’s natural wicking and odor-resistant properties keep you dry and comfortable while active in cold weather. The perfect base or mid layer for cold to freezing conditions make these thermal tops our warmest and thickest base layers yet! COMFORTABLE & CONVENIENT: These quick-drying shirts with a UPF Rating 50+ are perfect for your next trip, hiking, playing sports, whether your camping, skiing, hunting, or partaking in any outdoors activity.
BrandMERIWOOL #ad
ManufacturerMERIWOOL #ad
Height4
Length9.5
Width4.75

6. Smartwool

#ad

Smartwool Men's Merino 250 Baselayer Crew Charcoal Heather Medium Mens

#ad
Smartwool #ad - Slim fit. Cold weather base layer. Classic thermal merino. Designed to meet the demands of outdoor adventuring, this slim fit crewneck shows off a slimming silhouette while offering unrestricted movement through the arms and chest.

We've updated this fan-favorite with new colors and a new fit to improve functionality while enhancing aesthetics. Ideal for cold-weather activities where warmth and breathability are crucial, this midweight fabric used a 100% Merino wool construction that helps move moisture away from skin to keep you warm and dry. Functional features. From wool socks to base layers for men, women and kids, we aim to provide the highest quality apparel for your outdoor adventures with a commitment to environmental sustainability, racial equity and inclusivity.

Feel good. Go far. Go far, feel good with thoughtful tech to keep you trekking comfortably — interlock knitting enhances breathability, thermoregulation and moisture-wicking while flatlock seams minimize chafing for greater comfort. Add this cold weather base layer to your winter wardrobe and experience the difference on your next adventure.
BrandSmartwool #ad
ManufacturerSmartwool #ad
Height2
Length5
Weight0.6
Width4
Part NumberSW016349010-M
ModelSmartwool

7. DEVOPS

#ad

- L, DEVOPS 2 Pack Men's Thermal Turtle Mock Neck Shirts, Compression Long Sleeve Tops

#ad
DEVOPS #ad - Ultra soft & warm thermal tech fleece fabric of the baselayer caresses the skin so naturally providing maximum comfort and softness. 90% polyester, 10% Spandex. Versatile performance thermal Tops with ultra soft hand feel and heat-retention is a perfect option during various indoor activities, outdoor excursion and recreational activities. Stretchy & durable spandex added for extra stretch and shape retention; close-fitting style does better in retaining body heat to keep you warm. Easy care Machine Washable.
BrandDEVOPS #ad

8. DEVOPS

#ad

XXL, DEVOPS 2 Pack Men's Thermal Long Sleeve Compression Shirts, 1# Black/White

#ad
DEVOPS #ad - Easy care Machine Washable. Stretchy & durable spandex added for extra stretch and shape retention; close-fitting style does better in retaining body heat to keep you warm. 90% polyester, 10% Spandex. Versatile performance thermal Tops with ultra soft hand feel and heat-retention is a perfect option during various indoor activities, outdoor excursion and recreational activities. Ultra soft & warm thermal tech fleece fabric of the baselayer caresses the skin so naturally providing maximum comfort and softness.
BrandDEVOPS #ad

9. Merino.tech

#ad

Merino.tech Merino Wool Base Layer, Mens 100% Merino Wool Long Sleeve Thermal Shirts Midweight + Wool Hiking Socks Large, Black 250

#ad
Merino.tech #ad - Super soft & comfortable – 100% superfine 17. 5 micron merino wool mens base Layer provides all day comfort and no itch! Designed for daily wear without rubbing, overheating, or bunching of regular cotton.

Moisture wicking & odor resistant – merino base layer mens natural wicking and odor-resistant properties allow it to absorb moisture better than any other fabric, keeping you dry and fresh. Breathable – for longer lasting wear, hand wash and lay flat to air dry. Midweight – mens merino base layer available in: lightweight = 165 g/m², Midweight = 230-250 g/m², Heavyweight = 320+ g/m².

If your merino. Tech mens merino wool base layer does not perform to your satisfaction, return it within 60 DAYS for a hassle-free refund, exchange, or replacement. Men's merino wool top naturally regulates body temperature to keep you comfortable all year round. Lifetime warranty – all merino. Tech products are covered by our lifetime warranty.
BrandMerino.tech #ad
ManufacturerMerino.tech #ad

10. Roadbox

#ad

Roadbox Mens Thermal Underwear Fleece Lined Long Sleeve Tops & Tights Athletic Warm Base Layer as Black

#ad
Roadbox #ad - The soft fleece lining inside can lock in heat and bring extreme warmth in winter. You can buy our men's warm product for builders, roofers, bushcraft instructors and those who work in cold weather. Giving your freedom of outdoor activities, never have bound feeling.

Soft & warm92% polyester and 8% spandex. The outside of men's thermal underwear is made of wind-proof thermally active fabric. Best gift warmth is the best gift in the cold winter. Multi-function men's thermal tops and bottoms can be used as pajamas, or base layer under the jacket. Elasticity designthe men's thermal long johns uses a four-way stretch fabric to provide excellent comfort and all-around exercise to stretch your muscles.

It can absorb the sweat produced during exercise to the clothing's outer surface to prevent skin stickiness and unpleasant smell, keeping you dry and comfortable. Ideal for outdoor and indoor sports like Gym training, sportswear, Fishing, home wear, Hiking, Cycling, Jogging. Quick dry & breathablethe men's warm base layer uses moisture-wicking and breathable fabrics.
BrandRoadbox #ad
ManufacturerRoadbox #ad
Part NumberRB9018152_05-black-XXL
ModelRB9018152