What Are The Best Thermal Base Layers in 2025

Fleece-lined, thermal underwear set for women for superior warmth and comfort.

This WEERTI thermal underwear for women is a two-piece set, including a long-sleeved top and full-length bottoms. It features a fleece lining for added warmth during cold weather, making it an excellent base layer for outdoor activities or lounging at home. The fabric is breathable, moisture-wicking, and stretchy for comfort and flexibility.

Eco-friendly, warm waffle thermal underwear bottoms by Fruit of the Loom.

Fruit of the Loom's thermal underwear bottoms are made from recycled polyester, offering a greener choice in comfort. The waffle fabric creates pockets of trapped warm air throughout the garment, retaining body heat close to the skin, and the elastic waistband and ribbed cuffs ensure a snug and secure fit.

Warm, flexible, and breathable thermal underwear set perfect for winter sports and hunting.

The CL convallaria Thermal Underwear Long Johns Set is a high-quality thermals designed for winter sports and hunting. Made from a blend of polyester and spandex, it's breathable, moisture-wicking, and offers four-way stretch for comfort and freedom of movement.

Durable, warm, and moisture-wicking men's thermal bottom.

The Carhartt Men's MBL115 Base Force Midweight Base Layer Classic Bottom is a dependable, comfortable lower body thermal layer. It's designed for warmth and durability, made from 100% polyester with FastDry® technology for quick-wicking and Stain Breaker® technology to release stains.

Women's fleece-lined thermal set for comfort and warmth in cold weather.

This thermal base layer set from Cuddl Duds features a long sleeve shirt and leggings, both lined with cozy fleece for extra warmth. Designed specifically for cold weather, it's perfect for lounging and layering, providing both comfort and heat retention.

Complete, versatile thermal underwear set made from Merino wool.

The Merino.tech Wool Thermal Set is a complete thermal underwear outfit for men containing both top and bottom pieces. Made from Merino wool, it is available in heavyweight, midweight, and lightweight options, making it a versatile choice for various levels of cold exposure.

Fleece-lined, thermal base layer set perfect for cold winter weather.

The TELALEO Thermal Underwear Set is a high-quality, cold-resistant base layer designed for extreme winter weather. Consisting of two sets of long johns and shirts, it's made with fleece lining for maximum warmth and comfort. The fabric is not only thermal but also breathable, lightweight, and moisture-wicking, ensuring optimal comfort during any winter activity.

3/4 Pack Women’s Thermal Shirts, Women Fleece Lined Compression Long Sleeve Base Layer Tops for Wint

Amazon product: 3/4 Pack Women’s Thermal Shirts, Women Fleece Lined Compression Long Sleeve Base Layer Tops for Winter Cold Weather

Lightweight, stretchy thermal base layer for women by 32 Degrees.

The Heat Women's Thermal Base Layer by 32 Degrees is a lightweight, form-fitting long sleeve top featuring 4-way stretch for ultimate comfort and mobility. This thermal layer is designed for insulation and moisture-wicking, making it an ideal choice for winter sports or cold weather outings.

Men's lightweight, stretchy thermal top perfect for layering.

This lightweight, form-fitting thermal top by 32 Degrees offers long sleeves and a crew neck for optimal warmth. It's made with a 4-way stretch material that ensures comfort and flexibility during any activity.