Do you need a separate permit for the Trans-Catalina Trail or just campground reservations?

There is no separate hiking permit: your campground reservations are the permit. The Trans-Catalina Trail requires you to sleep in designated campgrounds, dispersed camping is prohibited island-wide, and a complete set of camp bookings is what authorizes the thru-hike.

That structure has a sharp consequence: your itinerary is only as good as its weakest night. The trail's five camps are Hermit Gulch near Avalon, Black Jack at 1,600 feet in the interior, Little Harbor on the wild west-facing shore, Two Harbors above the isthmus, and Parsons Landing on the remote northwest beach. If one camp is full on the night you need it, the whole chain breaks, which is why experienced TCT planners book all nights at once, early. Reservations for the year open in January, and Little Harbor, often called the most scenic camp on the island, fills fastest for weekends. Fees run 30 to 45 dollars per night per campground.

Two camps carry special logistics. Parsons Landing has no running water, so you reserve a locker that comes stocked with water and firewood. And ferry seats to and from the island are their own reservation, easy to forget until peak weekends sell out.

If your dates are already blocked, single-night cancellations at the bottleneck camps do appear, and catching one can repair an otherwise complete itinerary. Watching the specific camp and date beats rebuilding the whole trip.