Flies by Month – River (UK Seasonal Guide)

River fly fishing in the UK is highly seasonal, with changing water temperatures, river flows, insect life, and fish behaviour shaping fly choice throughout the year. What works well in spring can be ineffective in summer, and autumn and winter often demand a completely different approach again.

This page brings together our month-by-month river fly selections, curated specifically for UK rivers. Each monthly collection reflects what is typically hatching at that time of year, alongside the subsurface food sources that remain important when surface activity is limited. Where relevant, the focus naturally shifts from trout to grayling as the season progresses.

These selections are not generic fly lists. As a specialist fly fishing retailer and professional coaching business, our advice is grounded in extensive on-the-water experience across a wide range of UK rivers. We spend thousands of hours each year fishing, guiding, and advising anglers on fly choice, depth, and presentation, and that practical knowledge shapes every collection linked below.

Use this guide to explore which flies are most effective throughout the river season, from early spring olives and summer terrestrials to autumn caddis and winter grayling patterns. Each month links to a dedicated river collection with more detailed guidance to help you choose the right flies for the conditions.

If you’re unsure which flies best suit your local river or the time of year you’re fishing, we’re always happy to help.