The Subway isn't a hike. It is a six-to-ten-hour wade-and-rappel traverse of a slot canyon that ends back at the Riverside Walk in Zion. The route earned its name from a section of canyon where the walls and floor have been polished into a tube that resembles a subway tunnel. Two versions exist — top-down (technical, with rappels) and bottom-up (non-technical, no ropes) — and both require a permit from the National Park Service.
Two routes, one canyon
The top-down version is a full canyoneering route. It starts at the Wildcat Canyon trailhead off Kolob Terrace Road, drops into Russell Gulch and Left Fork of North Creek, and includes multiple short rappels, swims through cold pools, and route-finding across slick limestone before reaching the Subway tunnel itself. The total distance is around nine miles with roughly fifteen hundred feet of descent. The bottom-up version starts at the Left Fork Trailhead on Kolob Terrace Road, climbs upstream through the same drainage to the Subway tube, and returns the way it came — non-technical, no ropes, but a strenuous nine-mile round trip with extensive wading and route-finding.
The permit system
Both versions require a permit from NPS Zion. The Subway is one of the park's headline permit canyons, and demand exceeds supply for most of the climbable season. Permits are allocated through a multi-tier lottery: an advance lottery several months out, a calendar reservation system, and a last-minute walk-up window at the Zion Wilderness Desk. Daily quotas are tight — typically a few dozen permits across both directions — and the system is competitive. Climbers who plan a Subway trip without a permit do not climb the Subway.
Cold water, flash-flood weather
The Subway runs water year-round, fed by the same drainage system that builds North Creek. Pools sit cold even in summer — wetsuits or drysuits are commonly carried — and full immersion is unavoidable on the top-down route. The bigger hazard is flash-flood weather. Slot canyons in Zion concentrate runoff fast, and the Subway has been the site of fatal flooding incidents during monsoon storms. The NPS posts canyon-specific weather windows; checking that forecast and the wilderness desk's daily call is non-optional.
Where it sits in the Zion canyoneering menu
The Subway is the headline canyoneering route in Zion and one of the most-photographed slot canyons in the United States. It is the route that introduces most canyoneers to the park's permit system, the cold-water reality of Zion slots, and the technical commitment of a full top-down descent. Climbers and canyoneers building a Zion trip typically pair the Subway with Pine Creek (a shorter intro technical canyon) or Keyhole (a fast beginner-friendly route) for a multi-day permit rotation. It is the slot canyon every Zion canyoneer has on their list before any other.