The short answer
March and April are prime time for big brown trout in Chilean Patagonia. Brown trout spawn in late autumn, and in the weeks before they feed hard and turn aggressive, which makes this the best season of the year for streamers and large terrestrial flies. Rivers are low and clear after summer, most anglers have gone home, and the valleys around Coyhaique are full of autumn colour. In Aysén, rivers are catch-and-release from 1 March, and the season closes on 6 May 2027.
Why autumn is the best season for big trout
Every fishing season in Patagonia has its strengths. December to February is the classic dry-fly season, with long days and steady hatches. But if your goal is the largest fish of your trip, many guides — and we — would point you to autumn.
Brown trout are getting ready to spawn
Unlike rainbow trout, which spawn in late winter and spring, brown trout spawn in late autumn and early winter. In the weeks before, they feed heavily to build reserves and become territorial. That combination — hungry and aggressive — is why autumn produces some of the heaviest browns of the year, and why a well-swung streamer can bring a violent take.
Some lake fish move into the rivers
As the spawn approaches, some large browns leave the lakes and move into the rivers that feed them. Fish that spend the summer out of reach in deep water become accessible to anglers on foot or in a drift boat.
Terrestrials are still on the menu
Late summer and early autumn are the season of beetles and grasshoppers in the open valleys of Aysén. On warm March afternoons, large foam patterns on the bank can still bring trout up to the surface. Rivers such as the Ñirehuao are famous for it — read our guide to fly fishing the Ñirehuao River.
Low, clear water and empty rivers
After the dry months of January and February, rivers are typically at their lowest and clearest in early autumn, which makes sight fishing easier. And with the summer crowds gone, you often have a beat entirely to yourself.
The 2026–2027 rules for autumn fishing in Aysén
Recreational fishing in Chile is regulated by Sernapesca, and rules are set each season. For 2026–2027 in the Aysén region:
| Water | Season period | Rule |
|---|---|---|
| Rivers | 12 October – 30 November 2026 | Catch and release |
| Rivers | 1 December 2026 – 28 February 2027 | Up to 3 fish or 15 kg per angler per day |
| Rivers | 1 March – 6 May 2027 | Catch and release |
| Lakes | 12 October – 9 November 2026 | Catch and release |
| Lakes | 10 November 2026 – 1 April 2027 | Up to 3 fish or 15 kg per angler per day |
| Lakes | 2 April – 6 May 2027 | Catch and release |
| Chinook salmon | 12 October 2026 – 15 January 2027 | Up to 2 fish per angler per day |
In practice, autumn on the rivers is catch-and-release fishing — which is how we and most guides fish anyway. Rules change every season, so always confirm the current regulations with Sernapesca before your trip.
- Licence: every angler needs a recreational fishing licence, bought online at pescarecreativa.sernapesca.cl and shown printed or on your phone.
- Didymo: clean, wash and dry your waders, boots and gear between rivers to avoid spreading the invasive algae Didymosphenia geminata. Felt soles are best left at home.
Where to fish in autumn
Aysén has thousands of kilometres of rivers and hundreds of lakes. These are the waters we return to most in March and April.
- Simpson River — Coyhaique's home river, with easy access and a good population of browns and rainbows. Ideal for a first day.
- Ñirehuao River — a meandering spring creek through open steppe, known for terrestrial fishing and wary browns. Fish it from Estancia Ñirehuao, a working estancia on its banks.
- Mañihuales and Cisnes rivers — larger freestone rivers north of Coyhaique, good for float trips and streamers.
- The lakes around Coyhaique — Pollux, Castor, Elizalde and others, known for large browns cruising the shallows. Autumn is a good time to fish the river mouths and drop-offs.
- Baker River — Chile's largest river by volume, turquoise and powerful, with big fish and a dramatic setting near Lago Bertrand. Best fished with a guide and a boat. Stay at The Bertrand Stay.
Flies, tackle and what to pack
- Rods: a 5 or 6 weight for rivers and spring creeks; a 7 weight for the Baker, the big lakes and windy days.
- Lines: a floating line plus a sink-tip or intermediate line for streamers and lake fishing.
- Flies: streamers (woolly buggers, zonkers, sculpin patterns) in olive, black and brown; foam beetles and hoppers for March afternoons; a few nymphs for cold mornings.
- Clothing: breathable waders and warm layers underneath. Mornings can be near freezing in April, and water temperatures drop through the month. Bring gloves, a warm hat and a good rain jacket.
- Timing your day: fish tend to be most active from late morning into the afternoon as the water warms. There is no need for dawn starts — which suits Aysén's late autumn sunrises (around 8 am or later in April).
How autumn compares with the rest of the season
| Period | What to expect |
|---|---|
| October – November | Season opens, high water from snowmelt, catch-and-release on rivers until 30 November. Good nymph and streamer fishing. |
| December – February | Classic dry-fly season. Long days, warmest weather, most anglers and lodges full. |
| March – April | Pre-spawn browns, streamers and terrestrials, low clear water, autumn colour, few anglers. Our favourite. |
| May (until 6 May 2027) | End of season. Cold, short days, most fishing lodges closed. |
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Combine it with the road trip
Autumn is also the best season to drive the Carretera Austral, and the two fit together well: a few days on the rivers around Coyhaique, then south through the lenga forests of Cerro Castillo to the Baker. Read The Carretera Austral in Autumn: A Road Trip Planner, or see why we think autumn is the best time to visit Patagonia.
Frequently asked questions
When is the best time to fly fish in Patagonia?
For the largest brown trout, March and April. For dry-fly fishing in the warmest weather, December to February. The season in Aysén runs from October to early May.
When does the fishing season end in Aysén?
For the 2026–2027 season, fishing in rivers and lakes closes on 6 May 2027. Rules change each season, so confirm with Sernapesca.
Can I keep fish in autumn?
Not in rivers: in Aysén, rivers are catch-and-release from 1 March 2027. In lakes, a limited catch is allowed until 1 April 2027, then catch-and-release until the close of the season.
Do I need a fishing licence in Chile?
Yes. Every visiting angler needs a recreational fishing licence from Sernapesca, available online.
Is autumn fishing in Patagonia good for beginners?
Yes, with a guide. Streamer fishing is simple to learn and the rivers are quiet, which makes it a relaxed time to start. Dress warmly — the mornings are cold.
Do I need a guide?
Not for the easiest-access rivers near Coyhaique, but a guide makes a large difference: access to private water across estancias, a boat on the bigger rivers and local knowledge of where fish hold in autumn.
Plan your fishing trip with us
We design private fly fishing journeys in Aysén with guides, lodges and estancias we know personally, and we can combine them with the rest of Patagonia. Share your dates and we will put together an autumn fishing trip for you.
Sources
- Sernapesca — Comenzó la temporada de pesca recreativa en la región de Aysén (13 October 2026)
- Sernapesca — recreational fishing licence portal
- Dirección Meteorológica de Chile — climate normals 1991–2020, Coyhaique Teniente Vidal (via Coyhaique climate data)
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