If you are planning to visit Zion, you must carefully study Zion's web site well in advance of your trip, especially the confusing part on the shuttle bus befora booking a trip Taking a bus (coach) tour that includes a visit to Zion National Park is a often a high risk gamble.
Drawing 500,000 more visitors a year than the Grand Canyon, Zion is perhaps the most popular destination national park (a destination national park is a National Park where the vast majority of visitors have to make a trip so long that they must spend at least one night in or near the National Park to have enough time to decently see it). USA's destination National Parks are often remotely located. Zion National Park is in two UT counties. The population density of one is 1.5 people per sq mile. The other, the local urban area, has a population density of 37 per sq mile (the UK: 679) Zion is in UT, population 3,100,000, but 4,000,000+ people every year come to Zion to see the 6 mile long (400 parking spaces) Zion Canyon, which is only accessible by park shuttle bus (UK: tram), except for a decreasing open window in mid winter. Advanced reservations are required and a ticket is good for only one round trip. I checked yesterday. For the next 11 weeks, there was only one day with a shuttle bus seat available. Reservations are only listed for a 12 week time period. There are no seats available this week, and just on one day in the remaining 11 weeks of the 12 week booking window.
Currently, new spaces on the shuttle are posted two days a month and some bookings are possible for the next day by lining (cuing) up at the ticket window at 5 pm, and good luck with that.
In reviewing one tour by coach (UK) or bus (USA), the Zion itinerary listed ‘stop 1: Visitor's Center; Stop 2: tram (shuttle bus)'. Did this tour provider book a seat on the shuttle for you? They don't say. Get a commitment from them in writing that you will visit Zion Canyon, and find out how long they allow for the visit-- rt on the shuttle is 90 minutes.
But then there, is a paradox . Visitor ratings of Zion National Park on places like TripAdvisor, the more reliable Google Maps ratings, and especially on tour purveyors' web sites, rave about their visit to Zion, and I'm pretty sure that none of the many bus tour visitors never got into Zion Canyon. Zion Canyon is ***** scenery. Odds are you live in * scenery. If you can't get into Zion Canyon, you will be only see **** scenery, and you will love it, but that's like eating Coq au Vin without the sauce.