3 Best Threads for Tying Dry Flies

In this article I want to answer a question that often comes from beginner fly tyers: which fly tying thread is best for tying dry flies? You can also browse our full range of threads here: fly tying threads .

There is no single perfect answer, but in my own tying I most frequently use three specific types of thread. They cover most classic dry fly patterns that many anglers tie.

70 Denier Flat Thread – Veevus or UTC

This is a fundamental thread for dry flies. Its main advantage is the structure – it lies flat on the hook shank. Thanks to this, you can easily build a smooth body and shape a gentle taper. It makes creating a proper dry fly profile quick and simple.

You can tie the entire mayfly body with thread alone, or use it as a base to wrap dubbing, feather fibres, peacock quill and many other materials.

The 70 denier size works perfectly for the most common mayfly and caddis patterns. If you prefer Veevus, you will find all variants here: Veevus threads .

When it comes to colours, it is worth having olive, brown, black and tan. Colour matters – wrapping a light material over a black thread will darken the body once the fly becomes wet.

A quick comparison: generally, Veevus threads feature slightly stronger fibres than UTC in the same diameter.

Ultra-Fine Double Thread – Veevus 16/0

This is a brilliant, ultra-fine yet very strong double-strand thread. The breaking strength of Veevus 16/0 is around 430 g, which means it is nearly as strong as UNI 8/0 – a thread roughly twice as thick.

The key feature is its two-fibre construction. You can easily split the thread by gently untwisting it between your fingers, insert materials such as CDC fibres or squirrel hair, twist everything back together and create a slim body or a soft hackle.

This allows you to tie delicate, low-bulk dry flies with excellent durability, especially useful for smaller patterns.

I truly enjoy working with this thread and highly recommend it!

GSP – The Strongest Fly Tying Threads (20–50 Denier)

GSP (gel-spun polyethylene) threads are made from extremely strong synthetic fibres. They lie flat, can be split easily and work perfectly for techniques where materials are inserted into the thread and twisted.

Whenever you need maximum thread strength – for example when tying down deer hair for caddis wings or trimming dense heads – GSP thread is the ideal choice.

Among brands offering GSP, two stand out with the best colour range and availability: Semperfli and Hends . At the time of writing this article, they simply offer more options than most competitors.

If you have any questions, feel free to contact me — I will gladly help you choose the right fly tying materials and threads so your dry flies fish even better.

Best regards,

Krystian Niemy