Simpson River at a glance
- Where
- Coyhaique, Aysén Region, Chilean Patagonia
- Joins
- The Mañihuales, forming the Aysén River
- Main tributaries
- Oscuro, Blanco Chico and Blanco Este near its source; the Claro further north; the Coyhaique just northwest of the city
- Type of water
- Freestone, fed by rain and snowmelt
- Fish
- Brown and rainbow trout
- Flow gauge
- DGA station Río Simpson bajo junta con Coyhaique (11317001-8)
- How we fish it
- By cataraft, two anglers per boat
Where is the Simpson River?
The Simpson is in the Aysén Region of Chilean Patagonia and runs past Coyhaique, the regional capital. Chile's water authority, the DGA, divides the Aysén basin into three river systems: the Mañihuales in the north, the Coyhaique in the centre and the Simpson, which drains the south. The Oscuro, the Blanco Chico and the Blanco Este feed the Simpson near its source, and the Claro joins it further north.
The Coyhaique River joins the Simpson immediately northwest of the city. Downstream, the Simpson meets the Mañihuales and the two form the Aysén River, which reaches the sea.
On the way to Puerto Aysén the river gives its name to the Reserva Nacional Río Simpson. According to CONAF, which manages it, the reserve lies at kilometre 37 of the road between Coyhaique and Puerto Aysén, covers 41,620 hectares and is crossed by Route 240-CH. The river runs beside the road and splits the reserve in two.
What kind of river is the Simpson?
A freestone river. The DGA classifies the Aysén basin as fed by rain and snowmelt, so the Simpson rises and falls with the weather. Our own readings show how quickly: in the week of 1 to 7 August 2026 the Simpson gained roughly 57% of its flow.
It is also cold water. On the morning of 7 August 2026 the Simpson read 2.0 °C at its gauge, against 7.6 °C on the Mañihuales, in the same basin and on the same morning. Our hydrological guide to Coyhaique's rivers explains what those numbers mean for a day on the water.
What fish are in the Simpson?
Brown trout (Salmo trutta) and rainbow trout (Oncorhynchus mykiss). The DGA's survey of the basin, which draws mainly on the Simpson and the Blanco, also records native fish: two Galaxias species and the pouched lamprey (Geotria australis). The same study lists the Simpson among the rivers of the basin suited to recreational fishing.
How do you fish the Simpson?
We float it by cataraft: inflatable frame boats on two pontoons that do the job a drift boat does on Western US rivers. Each cataraft carries two anglers. Because the Simpson moves with the weather, the day's drift is chosen on the day, from flow and wind.
On a freestone like this one, the useful approach depends on the flow: it can range from terrestrial dry flies near the banks to weighted streamers and sinking lines through deeper water. Some water is reached across private land, so we keep exact put-ins out of public copy. More on the rivers and lakes we float by cataraft.
Season and rules on the Simpson
The Simpson follows Sernapesca's rules for rivers in the Aysén Region, in the table below. We guide from 12 October to 30 April and release every fish. The full rules, the lake periods and how the licence works are in our guide to Aysén fishing rules and licence.
Aysén river rules, 2026–27 season
| Dates | Rule |
|---|---|
| 12 October – 30 November | Catch and release only |
| 1 December – 28 February | Up to 3 fish or 15 kg per angler per day |
| 1 March – 6 May | Catch and release only |
| 7 May – 11 October | Closed season |
Source: Sernapesca, management measures for recreational fishing, 2025–2027 seasons. Chinook salmon have their own season, and some spawning areas are closed all year. We guide from October 12 to April 30 and release every fish.
We float the Simpson River by cataraft out of Coyhaique. Catarafts are included in both programs where the water calls for them. See the rivers and lakes we float or what each program costs and includes.