Only 1. And depending on the weather there, some view points may be closed.
Plan on a 2 day trip so that you can soak in the sights of the Park. Mix and match with bus rides and hikes.
2 days @ Zion One day to ride the shuttle. 2 days if you want to see the norther paft of the park.i recommend it.
Depends on what you want to see. Some of the 9 stops along the bus route are a small hike to see scenic views. Other areas are longer hikes like the narrows and Angel's landing. There are a number of shops ain Springdale before you hit Zion. One day if you just want to drive into park. Keep in mind, you can only drive as far as Zion lodge (stop #5). The rest is accessed by bus, stops 6 to 9. Stop 7 currently closed...rock slide.
It depends on if you want to hike or not. The narrows would take you the whole day. There are more hikes in this park. But sightseeing I would say one full day.
One day is enough if you are only going to drive. If you want to see the viewpoints that require taking the bus, I'd recommend a second day.
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