Northern Patagonia Fly Fishing Report - 2026

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Northern Patagonia is one of Argentina’s most iconic trout regions, and the waters around San Martín de los Andes are already fishing more like mid-summer than early season. To get an accurate, on-the-ground look at how the season is shaping up, we checked in with Matías Arrenguren of Chimehuin Safaris, who has been guiding daily across the region’s rivers and lakes. Below is a current Northern Patagonia fly fishing report for 2026, including conditions, hatch activity, and practical insights for anglers planning a trip to San Martín de los Andes this season.

Season Progression and Current Conditions

The 2026 season in Northern Patagonia has been moving ahead of schedule. Lower-than-average snowpack led to rivers dropping earlier than usual, and warmer temperatures have accelerated both water conditions and insect activity across the region. As a result, many rivers are already fishing more like mid to late January, with improved wading access and more defined holding water.

Water clarity has been excellent on both rivers and lakes. While occasional thunderstorms briefly muddied sections of the Aluminé and Collón Curá, conditions stabilized quickly and cleared within a few days. The Chimehuin, Malleo, Caleufú, and Aluminé are all running at lower-than-normal levels for this point in the season, creating narrower channels and more fishable structure. Water temperatures remain favorable overall, generally holding in the mid-teens Celsius, though anglers should expect temperatures to continue rising as summer settles in in January and peaking in February.

Fishing quality has been strong across the board. Rivers have benefited from the earlier drop in flows in December, while lake fishing has been especially productive, with consistent surface activity and excellent opportunities on both dries and streamers. Overall, the combination of clear water, manageable flows, and early-season stability has set the tone for a very solid start to the season around San Martín de los Andes.

Hatch Activity

Dry fly fishing has been a clear highlight so far this season in Northern Patagonia. Both rivers and lakes have seen consistent surface activity, driven in large part by strong dragonfly and damselfly presence on stillwaters. Earlier in the season, smaller mayflies and caddis dominated much of the day, creating steady dry fly opportunities across a wide range of water types.

As conditions continue to settle into summer, hatch diversity has increased. Caddis and stoneflies have been especially active on the Chimehuin and Malleo, with notably large stoneflies showing on the Collón Curá. Anglers can also expect terrestrial fishing to become a bigger part of the program in the coming weeks, with hoppers, beetles, and the region’s well-known willow worm hatch beginning to factor more heavily into daily fly selection.

Overall, hatch timing has mirrored the accelerated season, with surface activity starting earlier and lasting longer throughout the day. Combined with clear water and stable flows, this has created excellent conditions for anglers who enjoy visual fishing and adjusting tactics as insect activity evolves.

Flies, Techniques, and Seasonal Progression

Fly selection in Northern Patagonia follows a clear seasonal rhythm, and this year has moved quickly into patterns more commonly associated with mid-summer. Early in the season, higher water typically favors streamer fishing on both rivers and lakes, with sinking and intermediate lines helping anglers cover flooded banks and faster currents. As flows drop and days lengthen, dry flies and attractor patterns become increasingly effective, especially during consistent mayfly and caddis activity.

This season, classic dry flies such as Adams, Cahills, and Purple Haze patterns have produced well in sizes ranging from #12 to #16. As light levels rise and insect activity increases, attractor and terrestrial patterns like Chubby Chernobyls, foam ants, beetles, and hoppers come into play, particularly during the warmest parts of the day. Evening fishing on the Chimehuin can also bring selective feeding during localized mayfly events, where matching size and profile becomes critical.

Streamer fishing remains productive throughout the season, especially on larger rivers and stillwaters. Woolly buggers, minnow imitations, and articulated-style profiles continue to account for larger trout, while nymphing with stonefly, mayfly, and caddis patterns fills the gaps between surface activity. Anglers should carry both beadhead and unweighted nymphs to adapt to changing depth and flow. It is also important to note that regulations in Northern Patagonia require single-hook streamers, so multi-hook patterns must be modified accordingly.

Equipment & Practical Advice

A versatile rod setup goes a long way in Northern Patagonia, where conditions can shift throughout the day. For light presentations and dry fly fishing, a 9-foot 5-weight is an ideal all-around choice. Paired with a weight-forward floating line, this setup offers the right balance of delicacy and control for clear water and technical presentations on rivers and spring-fed systems.

For lakes and indicator nymphing, a 9- to 10-foot 6-weight provides added reach and line control. Matched with a weight-forward floating line, this setup handles longer casts, heavier rigs, and changing wind conditions while remaining versatile enough for a wide range of water types. When streamer fishing or dealing with consistently windy conditions, an 8- to 9-foot 7-weight offers the power needed to turn over larger flies and maintain control. These rods pair well with both floating and sinking lines, depending on depth and current speed.

Beyond gear, understanding local rhythm and logistics can greatly improve the overall experience. Days in Argentina tend to start earlier and stretch longer, with fishing often best in the morning before popular areas see increased local traffic. Many shops and small businesses close midday, so organizing supplies ahead of time helps avoid downtime. Dining runs later than many visitors expect, and anglers who adapt to the local pace can enjoy relaxed evenings after full days on the water. Cash is still widely used and often rewarded with small discounts, making it worth carrying during your stay.

Dry Fly Rod:
T&T Avantt 2 9’ 5wt
Ross Animas Fly Reel
SA Amplitude Smooth Trout Fly Line

Lake / Nymphing Rod:
Hardy Marksman 10’ 6wt
Hardy Averon Fly Reel
SA Amplitude MPX Fly Line

Streamer Rod:
Orvis Helios D 8’5” 7wt
Lamson Litespeed F Fly Reel
Rio Predator Elite Fly Line

Conclusion

Northern Patagonia is shaping up for a strong 2026 season, with clear water, earlier-than-normal conditions, and consistent fishing across both rivers and lakes. The San Martín de los Andes region continues to offer a well-rounded experience, combining productive trout water with diverse fishing styles and a welcoming town that makes long days on the water easy to enjoy. For anglers considering a trip this season or planning ahead, local insight and timing remain key. Working with experienced guides and thoughtful trip planning can make all the difference in getting the most out of a Northern Patagonia fly fishing experience.

More Resources

The Ultimate Argentina Fly Fishing Guide

Questions?

If you’d like to learn more about fishing in Northern Patagonia, give us a call at 888-413-5211 or drop us a line at [email protected].