The Enchantments thru-hike climbs from the Stuart Lake Trailhead past Colchuck Lake, up Aasgard Pass and across the Core Enchantment Zone, a basin of granite and alpine lakes, then drops to the Snow Lakes Trailhead. The line this page draws is 18 miles (29 km), and the climb to the pass comes on the first two days.
It can be done as one very long day, which needs no overnight permit: day users fill out a free day-use permit at the trailhead and display a Northwest Forest Pass for parking. The catch is that the pass comes after 4.2 miles (6.8 km) of climbing to Colchuck Lake and the day is long, so a late start or snow on the pass can turn it into a retreat. This page is written as three days with a Core Enchantment Zone permit: Colchuck Lake, a night in the Core, then out.
The decision that matters is the permit, and it comes in February. The Core allows 24 people a day: 16 through the advanced lottery, which runs once a year, and 8 through the daily lottery. The permit page says demand for overnight permits far exceeds the number available and links the historical lottery statistics, which is where to look for odds; this page does not quote any. The daily lottery is a phone application the day before, and only from inside Leavenworth (details under Permits), so it suits a flexible trip, not a booked one. The permit page also names a lesser trip: a Colchuck or Snow Zone permit (3 and 5 groups a day) with a day trip into the Core, which is an out-and-back from one lake, not this route.
Direction is your call. A Core permit lets you enter or exit by either trail, and the official pages state no preference. This page goes up Aasgard Pass: 4.2 miles (6.8 km) and 2,100 feet (640 m) to Colchuck Lake, the pass, then the long way down the Snow Lakes trail. The other way you climb the Snow Lakes trail (6.5 miles (10.5 km) and 4,100 feet (1,250 m), then steep granite slabs) and come down the pass, which the Forest Service's snow warning covers as much as the climb. In this direction the mapped line climbs about 5,000 feet (1,530 m) in total.
Dated note (1 November 2026): the 2026 overnight season ended on 31 October. From 1 November to 15 May overnight permits are not required and the Forest Service asks visitors to self-register at the trailhead, but the permit page says nothing about winter conditions, so check the Forest Service page before any trip in those months.