It’s one of the most common questions in fly fishing—and rarely a simple one. Weather, water levels, and seasonal patterns always play a role, whether you’re fishing close to home or travelling halfway around the world for taimen.
Mongolia offers outstanding fly fishing from mid-June through October. The “best” time depends on the river, the region, and what you want to experience. Each part of the season offers different conditions and opportunities.
Mongolia’s legal fishing season runs from June 15 to November 1.
The fly fishing we offer is on two distinct river systems, located roughly 800 kilometres apart in very different regions of the country. This allows us to focus on each river during the period when conditions are typically most favourable.
Fish Mongolia (western river) operates from mid-June through to mid-September
Mongolia River Outfitters (eastern river) from late August through to October
Within these windows, guests generally experience good water conditions, productive fishing, and comfortable seasonal weather—while recognising that these are wild, remote rivers.
Western Mongolia: mid-June to mid-September
Spring runoff has usually subsided by early June and the river is generally low and clear by the time the season opens. Early summer offers excellent visual fishing, with taimen feeding aggressively on surface patterns, including large mice.
As summer progresses, brief mountain thunderstorms can temporarily raise water levels, but the river typically drops and clears quickly. These storms often help keep water temperatures cool, maintaining active fish behaviour.
Mid-summer brings outstanding trout fishing for lenok and grayling, with hopper fishing and attractors producing consistently.
By August, cooler nights and stable conditions often coincide with encounters with some of the largest taimen of the season, as fish feed heavily in preparation for winter. September can bring colder nights and early storms, but cool water frequently translates into excellent fishing.
Eastern Mongolia: Late August to October
Eastern Mongolia receives more consistent monsoonal rainfall during mid-summer. By late August the rains subside and flows typically drop and clear, marking the start of prime fall fishing.
September often brings warm days, cool evenings, and spectacular fall foliage. As October approaches, temperatures begin to drop and winter conditions begin to set in. Camps are well equipped with wood-burning stoves, and colder water often triggers intense feeding behavior as taimen prepare for winter.
Dry-fly opportunities are more common earlier in the fall, while sink-tips and streamers become increasingly effective later in the season. Trout fishing is typically strongest earlier, with opportunities for large Amur pike increasing toward late fall.
Weather, Water and Wild Rivers
Although these operating windows are based on long-term conditions, but these are remote, natural river systems. Weather can change quickly, and precipitation can occur at any time.
Clear skies and favourable water conditions are common—but never guaranteed. Snow flurries, bright sun, and short-sleeve weather can all occur within the same day.
Taimen are aggressive predators and feed in a wide range of conditions. Higher or off-colour water often brings fish tight to the banks, while low, clear water creates opportunities for sight-casting on shallow flats.
To sum up, if you are looking for a fly fishing adventure in an extraordinary destination, you should add Mongolia to the list. No crowds, great guides and a chance to unwind with some big fun and big fish. More details on what to expect and current availability can be found our our blog ‘The search for the River Wolf, 2026 and 2027‘.
Aardvark McLeod can arrange fly fishing holidays to several rivers in Mongolia. If you would like more information on booking a fly fishing holiday to experience some truly memorable taimen fishing please contact Alex Jardine or call our office on +44(0)1980 847389.
