About this permit
Cathedral Lakes is a Yosemite wilderness permit for the trailhead of the same name on Tioga Road, at the west end of Tuolumne Meadows. NPS rates its permit demand "Very High" and gives the trail as 7.6 miles round trip with 1,000 feet of gain, short enough that most of the competition is for the destination rather than the mileage.
The daily quota is 25 people, released the way every Yosemite trailhead is: 15 through the weekly lottery 24 weeks out, and the remaining 10 seven days in advance at 7 am Pacific. The park is direct about the rest: "No permits are set aside for walk-ups."
The trail is on the John Muir Trail almost immediately, so this permit also functions as the low-effort entry to the Cathedral Range, Sunrise Lakes, and the 22-mile JMT descent to Yosemite Valley.
The route
NPS puts the round trip at 7.6 miles with 1,000 feet of gain and a 6 to 7 hour day-hike estimate, so as a backpacking trip this is a short walk in and a lot of time at the lakes. Parking is along Tioga Road on the west side of Tuolumne Meadows, and the trail heads south from the road. Overnight parking with food storage is also available at the Tuolumne Meadows Visitor Center.
The climb is continuous but never steep. The spur to Lower Cathedral Lake breaks off near the top of the climb and runs 0.7 mile one way; the main trail continues to Upper Cathedral Lake. Both basins are closed to campfires, and Yosemite's four-mile rule means you cannot camp within four trail miles of Tuolumne Meadows, so plan where you stop before you leave the car.
Beyond the lakes you are on the John Muir Trail with real options: Long Meadow and Sunrise High Sierra Camp to the south, Sunrise Lakes to the west, or the full 22 miles down the JMT to Yosemite Valley, which NPS notes is "mostly downhill" in that direction and more than 5,600 feet of climbing in reverse.
Why it matters
NPS rates permit demand for this trailhead "Very High," and the reason is geography rather than hype. The trail leaves Tioga Road on the west side of Tuolumne Meadows and is on the John Muir Trail within a couple of miles, which makes it the cheapest entry in the park to the high country. From the lakes you can keep going to Long Meadow, Sunrise High Sierra Camp and Sunrise Lakes, or turn south-west and walk the JMT 22 miles down to Yosemite Valley, mostly downhill.
The feeling
You leave the road in lodgepole forest and climb steadily, and the granite keeps interrupting the trees until the trees give up. Cathedral Peak stands off to the left the whole way. Near the top of the climb a spur drops 0.7 mile to Lower Cathedral Lake in its granite bowl; the main trail carries on to Upper Cathedral Lake right under the peak. Both sit above 9,000 feet, which means the nights are cold in July and the sky is very dark.
