Short answer
Pima cotton is a premium, soft cotton suited to warm weather and easy-care everyday clothing. Merino wool is a fine wool that tends to be warmer, handles moisture and odor well, and works across a wider range of temperatures. Pima is usually easier and cheaper to care for; merino is usually the better choice for cool weather, travel, and active use.
What pima cotton is
Pima is an extra-long-staple cotton, meaning its fibers are longer than those of ordinary cotton. Longer fibers can be spun into smoother, stronger yarn, which is why pima is associated with softness and fewer pills (see fabrics that don’t pill). It is grown mainly in Peru, and also in the United States and Australia, and it makes up a small share of world cotton production. Retailers often describe it as soft, durable, and color-retentive; treat these as general claims, since actual quality depends on the garment’s construction.
What merino wool is
Merino wool comes from merino sheep and is made of very fine fibers, which is why it feels softer and less scratchy than coarser wool. It is widely used for base layers, socks, knitwear, and activewear. Merino is often valued for temperature regulation, moisture handling, and odor resistance.
Softness and feel
Both can feel soft against the skin. Pima has a smooth, cool, and crisp hand, while merino tends to feel springier and cozier. Sensitivity differs from person to person, and some people find even fine wool irritating, so try a small item first.
Warmth: is merino warmer than cotton?
Generally yes. Merino traps air and continues to insulate when damp, while cotton, including pima, offers less insulation and feels cool when wet. That makes pima a better match for mild to hot weather, and merino a stronger option for cool or variable conditions.
Breathability and moisture
Pima cotton is breathable and absorbent, which is comfortable in dry heat, but like other cotton it holds moisture and dries slowly. Merino can absorb moisture vapor and tends to feel less clammy during activity. Weight and knit affect both; see is wool more breathable than cotton for more detail.
Durability, pilling, and care
Pima is commonly sold as more pill-resistant and long-lasting than standard cotton, and it generally goes through the washing machine without fuss. Merino is also durable and elastic, but it needs more careful handling: follow the care label, since heat and agitation can shrink or felt wool. Many merino garments are machine washable on gentle cycles and air dried, but not all.
Pima vs Supima vs Egyptian cotton
- Pima: a type of extra-long-staple cotton, grown in Peru, the US, and Australia.
- Supima: a trademarked brand of American-grown pima cotton, with a certification program behind it (see Supima vs regular cotton).
- Egyptian cotton: a different long-staple cotton associated with Egypt (see Egyptian vs regular cotton), also sold as a premium cotton. Labels are not always reliable, so look for certifications where available.
Disadvantages of Supima and pima
- Higher price than regular cotton.
- Still behaves like cotton: slow to dry, wrinkles, and can shrink if washed hot (see does cotton shrink in the wash).
- Branding and labeling can be inconsistent, so quality varies by maker.
- Less insulating than wool in the cold.
Which merino brand is best?
There is no single best brand, and a ranking would depend on current products and what you need. Instead, look at fiber content, fineness, the garment’s weight, knit quality, care instructions, and reviews from people who have worn it for a while. Higher merino content is not automatically better if the construction is weak.
Which to choose
- Warm weather, casual wear, easy laundering: pima cotton.
- Cool weather, travel, hiking, and odor control: merino wool.
- Both: many people wear pima for summer basics and merino for layering.
For the broader comparison, see which is better, wool or cotton.