You need 2 days to visit the park properly, but you could do it in 1.
This is a popular park. Its proximity to Vegas brings even more visitors. Consider visiting on a weekday. Get there are early, around sunrise.
Think about combining a visit to Zion NP with Grand Canyon North Rim, Bryce Canyon NP and Cedar Breaks NM. For a 2-week itinerary through 7 National parks in Nevada, Arizona and Utah, see this page.
The park uses a shuttle – you want to arrange tickets in advance. Without access to the shuttle, you might miss out on many of the main attractions inside the park.
If you are unable to get shuttle tickets, you can book private tours that will take you inside the park, or ride bicycles.
Try to stay in Springdale, UT and take a shuttle from there into the park.
Itinerary
Riverside Walk (3.5/5)
Bus Station (shuttle stop 9)
Angels Landing (shuttle stop 6 Grotto)
As of July 2020, the final chain section up to Angel’s Landing is closed due to COVID-19. Take the West Rim Shuttle to The Grotto shuttle stop.
Lower Emerald Pools Trail (4/5)
The Watchman Trail (3/5) (shuttle NOT required)
Park at the Visitor Center
Watchman Trail is 3.1miles with 650feet elevation change
Pa’rus Trail (shuttle NOT required)
Park at the Visitor Center
3.4miles, 150feet elevation change
Canyon Overlook Trail (5/5)
There is a small parking lot on the right hand side right after you come out of the tunnel traveling east (toward Mt Carmel). You can only park here if you are driving in the eastbound direction (Zion to Mt Carmel). If you are traveling westbound (Mt Carmel to Zion), you cannot turn into this parking lot. Park along the road before you get to the parking lot. If you get to the parking lot, you will have to go through the tunnel to the Zion side, then turn around to come through the tunnel again, and then park.