Supima cotton: why it's considered the finest in the world

There is a cotton that feels different the moment it touches your hand – cooler, smoother, with a soft sheen that catches the light. Supima cotton belongs to a small, exclusive class of cotton with extra-long fibres, and it is precisely that fibre length that is the secret behind the feel. In this guide we cover what Supima cotton actually is, why it is so often called the world's finest cotton, and how it feels to sleep in night after night. It is the hotel feeling brought home, woven from one of the earth's rarest raw materials.

What is Supima cotton?

Supima cotton is a trademark-protected name for the highest-quality American Pima cotton – a so-called extra-long-staple (ELS) cotton. The name is a contraction of "Superior Pima". Unlike ordinary cotton, where the fibres are short and vary in length, Pima is distinguished by unusually long, fine and even fibres.

What makes Supima special is both its origin and its rarity. According to a review by the heritage brand Sunspel, Supima is grown exclusively in the USA and accounts for only around 3% of all cotton grown in the USA and less than 1% of all cotton in the world. That such a small share of the world's harvest meets this grade says something about why the material is perceived as luxurious.

Why fibre length makes all the difference

The difference between ordinary cotton and Supima comes down almost entirely to the fibre. Pima fibres are roughly twice as long as ordinary cotton – around 3–4 centimetres versus the bare centimetre of ordinary Upland cotton. The longer fibre can be spun into a finer, smoother and stronger yarn, because fewer fibre ends stick out along the thread.

The result shows in several ways in the finished bedding:

• Softness. Fewer protruding fibre ends give a smoother surface against the skin – a softness that often becomes even more pronounced after the first few washes.
• Sheen. The long, even fibres reflect light more uniformly and give the characteristic, discreet lustre.
• Durability. Longer fibres mean a stronger thread that withstands many washes and years of use without losing its shape.
• Less pilling. Because fewer short fibres come loose, less pilling forms, so the surface stays smooth for longer.

Sunspel describes Supima's three signature qualities in exactly this way: strength, softness and colour retention – qualities that make garments and textiles "look good but also wash and wear well". These are precisely the qualities you want next to your body for eight hours every night.

Sheen is not gloss – it is light

Many people confuse Supima's sheen with a shiny, synthetic gloss. They are two different things. Sheen is a soft, living light that comes from within the fibre itself, not a surface treatment. That is why a good Supima sheet looks expensive without looking artificial – it shimmers calmly rather than glints.

Supima and the hotel feeling at home

The luxurious feeling in a well-made hotel rarely comes down to a single detail. It comes down to materials chosen to feel good night after night, and that withstand industrial laundering without wearing out. Supima cotton suits that ambition perfectly, because its durability and softness live side by side.

In our range, it is the Regency Lee duvet cover set that carries this feeling. Regency Lee is woven in 100% Supima cotton with a thread count of 300 in a smooth, dense sateen weave that gives precisely that lustrous, durable surface. If you want to build the bed up piece by piece, there is also the Regency Lee sheet and pillowcases in the same quality. You will find the whole range gathered in our Supima cotton collection.

What thread count means – and why more isn't always better

Thread count is the number of threads per inch in the weave, horizontally and vertically combined. It is a measure that is often misunderstood. A very high thread count requires thinner threads to fit, and the quality of the fibre itself determines how good those thin threads turn out.

With a long, strong fibre like Supima, you don't need to chase extreme numbers. A thread count of around 300 in Supima gives a weave that is dense and smooth yet still breathes – the balance between softness and weight that feels indulgent without becoming stuffy. That is why Regency Lee lands at 300: it is the fibre, not the number alone, that does the work. If you want to delve deeper into how the weave affects the feel, we have written more in the guide to percale and the crisp hotel weave.

Sateen or percale – two paths to the same luxury

Supima can be woven in different ways, and the weaving technique changes the experience just as much as the fibre. Regency Lee is woven in a sateen weave, which gives the smooth, coolly shimmering surface. A percale weave gives instead a more matte, crisper and airier feel – think freshly ironed sheets. Our Ralph duvet cover set, for example, is a percale with a thread count of 200, for those who prefer the cooler, more sporty expression.

Which one suits you is about temperature and feel rather than quality – both can be wonderful. We have compared them side by side in the article percale or Supima, so you can more easily find the right one. And if you want to think about the bed as a whole, the guide on building the perfect bed layer by layer will help you combine sheets, duvet covers and pillowcases.

Safe against the skin: OEKO-TEX certified

A fine-fibre cotton is only half the story – what lies against the skin should also be free of unwanted chemicals. Regency Lee is OEKO-TEX certified to STANDARD 100. That certification means that every component of the textile – thread, stitching and trims – has been tested against more than 1,000 harmful substances and judged safe for skin contact. For a material you sleep against every night, that is a reassurance that feels just as important as the softness.

Care for your Supima and it will last for years

One of the points of Supima is precisely its durability – but it rewards a little care. Wash in lukewarm water, avoid fabric softener that settles like a film over the fibre, and avoid overdosing detergent. Air-dry or tumble-dry gently, and the weave will keep its sheen and only soften with time. We have gathered our best advice in the care guide for bedding.

If you want to see which of our sets customers keep coming back to, you'll find them among the bestsellers, and more complete solutions in the duvet cover set collection.

Frequently asked questions

What is Supima cotton?

Supima cotton is high-quality American Pima cotton with extra-long fibres (ELS), sold under the protected trademark Supima. The long, fine fibres give a softer, stronger and more lustrous thread than ordinary cotton.

Why is Supima called the world's finest cotton?

Because Supima makes up less than 1% of the world's cotton harvest and has unusually long fibres that give a combination of softness, sheen, durability and colour retention that ordinary cotton rarely reaches.

Is Supima the same as Pima cotton?

Supima is a guaranteed American-grown Pima cotton of top quality. All Supima is Pima, but only Pima grown in the USA that meets the trademark's quality requirements may be called Supima.

Which Supima product does Boe have?

Our Regency Lee is woven in 100% Supima cotton with a thread count of 300 and is OEKO-TEX certified. It is available as a duvet cover set, sheet and pillowcases in the Supima cotton collection.

Does thread count matter most for quality?

No, the quality of the fibre is most important. With a long, strong fibre like Supima, a thread count of around 300 gives a dense, smooth and breathable weave without having to chase extreme numbers.