The San Juan's tailwater character makes it one of the most consistent fisheries in the American West. Fed by the cold depths of Navajo Reservoir, the river maintains near-perfect temperatures year-round. The Quality Waters section — roughly three miles below the dam — is catch-and-release and holds the highest concentrations of large fish, where trophy rainbows in the five-to-eight-pound range are a realistic daily expectation and double-digit fish are caught with surprising regularity.

Flies on the San Juan are defined by the midge: size 20–26 patterns in red, black, and cream dominate throughout the year, with San Juan Worm and small Baetis nymphs rounding out a productive selection. A 4-weight rod with a 12–15 foot fluorocarbon leader and fine tippet is standard. For anglers who have never experienced this level of fish density and size, the San Juan is a genuinely eye-opening experience.