Mens Long Johns Thermal Underwear

Comfortable, warm, and ultra smooth merino wool thermal underwear for men

Be at your most comfortable when lounging about at home in Smitten’s super-soft merino wool thermal underwear. Merino wool is a natural fibre with excellent thermal properties allowing you to stay at a comfortable temperature no matter the season or weather conditions.

Our men’s thermal underwear can be worn as a warm insulating base layer, long johns, sleepwear, or exercise wear. These versatile pieces are practical for everyday use, whether you’re relaxing at home, going to the gym or out on a hike.

Smitten’s merino wool thermals have been worn by police and rescue personnel, so you can depend on their comfort, flexibility, and durability.

Quality thermal base layers for ultimate style and comfort

More than underwear, Smitten’s range of men’s thermals come in a wide range of colours and patterns making them ideal for wearing as inner layers or outer layers.

Superfine merino wool is a naturally breathable textile that feels amazingly soft and smooth against your skin. Whether it's winter or summer, these thermal bottoms will be your best friend ensuring you’re at the perfect temperature at all times.

Our men’s thermals are loved by hikers and joggers for their amazing warmth, flexibility, stretch, and skin-feel. When it comes to caring for your thermals, it’s a hassle-free process. Just put them through the washing machine and you will enjoy your pants for years to come!

Save money with quality thermals designed to last. You will look and feel your best when out on a hike, hanging out at home, travelling, running errands or going to the gym. With incomparable quality, you will be constantly reaching for them in your wardrobe.

Ethically Sourced Wool from Australian Producers – caring for animals and caring for you

At Smitten Merino, we’re committed to producing high quality garments that don’t come at the cost of the planet. Our wool is sourced from non-mulesed sheep on Australian farms who have enjoyed a cruelty free lifestyle. The wellbeing of our customers is of the utmost importance to us, which is why we make sure all of our pieces undergo thorough quality control checks before you put them on your body. In the end, you get a luxurious quality piece of merino wool clothing that feels and looks amazing.


Merino wool is a natural fibre with unique and wonderful qualities. It has thermal properties which help to regulate your body temperature, and is kind to sensitive skin. Sewn by a team of talented women, each of our garments is made with care and the closest attention to detail.

Men's Long Johns Thermal Underwear | Made in Tasmania. Inspired By Nature.

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