Is it possible to visit these four big dolomite attractions all in one day?

Depends on where you are coming from and how much hiking you plan on doing.

Plotting it on google maps shows its 60 miles ( 2.5 hrs) of driving time, (add for traffic), from Lake Prags ( Pragser Wildsee) to Val Gardena

Thanks for the quick response, Joe!

We will be traveling from Innsbruck and set aside all day (i.e. leaving very early and getting back very late) to see the some of the highlights of the Dolomites .

Ideally, we would like to do 3-4 hours of hiking/sightseeing, but are willing to be realistic.

How much time would people suggest in order to enjoy each of these sites?

Again, thanks!

Are you staying in the Val Gardena at the end of the drive or trying to return to Lake Prags?

If the former, it could be a nice drive for changing locations with the possibility of getting out for some light hiking. Getting to the Tre Cime and Rifugio Auronzo is a bit time consuming to get to. Don't know if you have seen it, but here are directions for access. The Tre Cime is not really a drive by.

If the latter (i.e. a round trip to/from Lake Prags), then it is, to me, a long day trip with 6+ hours in the car and not much time for 3-4 hours of hiking.

As Laurel said, you have 6+ hours of driving; google maps show 6+ hrs and I have found they are "optimistic" with their time estimates

It looks doable, but hopefully you have a low key day scheduled the following day.

The Monte Piana access road is closed to private traffic so you need a couple of jeep shuttle runs; depending how much time you want to spend on top, you may need a few hours only for that destination.

Wow! Thank you for all the responses!

We will be starting and ending in Innsbruck. And it is our only day like this on our whole trip.

However, it may be wise to take some of your counsel and not push it too much and cut back something.

So, if given the choice between Monte Piana and Tre Cime, which should we hike/explore and which should we cut? Which in your humble opinions is more beautiful?

Again, thank you for all the responses!

If you mean by seeing Tre Cime you want to take the multi-hour roundtrip hike/walk from the parking lot to see it up close then your 1 day plan is not feasible. if you plan on driving to each spot and looking from parking lots at each or staying no more than 1 hour per location than yes it is possible.
To me it is not clear by what you mean by Val Gardena, this is more a region made up of multiple towns than an attraction or single mountain.

A realistic plan from Innisbruck would be drive in the early morning to Lake Prags, spend an hour walking around the pretty glacier lake, Head from there to the Tre Cime toll road which is not very far from Lake Prags, do the R/T hike there and then head back to Innisbruck the same day, you will be quite tired with this plan, no reason to head to the other spots and Tre Cime probably offers the most scenery for a 1 day trip such as this.

Ideally your 1 day will be a weekday and not a weekend in August as these locations all get very crowded on August weekends.

Thank you for the input.

Our plans, as of now, are to spend an hour or so at Lake Prag, drive over to and hike at either Tre Cime or Monte Piana, and then drive through the Alpe di Suisi / Val Gardena region on our way back to Innsbruck (maybe stopping to eat somewhere with a view).

Does the "Great Dolomite Road" drive through the Alpe di Suisi / Val Gardena region?

-Michael

That is a good plan if you can actually leave very early and return very late.
You have about 7 hours of just driving, you have at least 6 hours of stops plus any time for meals on top of that so you are talking a true like 6 AM til 10 PM type of all day outing.

You could drive very scenic mountain passes between Tre Cime and exit out the other end on the highway which heads north to Innisbruck so that way makes sense for you to go. It will be longer than returning the same way you came because mountain pass driving is slow driving but mileage wise this is likely the shorter route.

Below are 2 options, both would take you over multiple mountain passes and be extremely scenic and also winding
https://www.google.com/maps/dir/Auronzo+di+Cadore,+Province+of+Belluno,+Italy/Urtij%C3%ABi,+Province+of+Bolzano+-+South+Tyrol,+Italy/Innsbruck,+Austria/@46.892751,11.3143468,9z/data=!3m1!4b1!4m20!4m19!1m5!1m1!1s0x4779ce97d875050f:0x407098715915320!2m2!1d12.3591123!2d46.5635366!1m5!1m1!1s0x477812f9a780dbb9:0x3ad835b22896a03b!2m2!1d11.6742025!2d46.5734348!1m5!1m1!1s0x479d6ecfe1f8ca73:0x9d201c7d281d9b0d!2m2!1d11.4041024!2d47.2692124!3e0

https://www.google.com/maps/dir/Auronzo+di+Cadore,+Province+of+Belluno,+Italy/ortisei/Innsbruck,+Austria/@46.5151076,11.9148183,12z/data=!4m25!4m24!1m10!1m1!1s0x4779ce97d875050f:0x407098715915320!2m2!1d12.3591123!2d46.5635366!3m4!1m2!1d11.7831644!2d46.5006326!3s0x47786a9af496f443:0xeec49ab79baab5a1!1m5!1m1!1s0x477812f9a780dbb9:0x3ad835b22896a03b!2m2!1d11.6742025!2d46.5734348!1m5!1m1!1s0x479d6ecfe1f8ca73:0x9d201c7d281d9b0d!2m2!1d11.4041024!2d47.2692124!3e0

You will drive right past/through the Val Gardena area but that part won't really be very scenic the mountain passes you drive through before it will be which are the portions usually detailed as the highlights of the Great Dolomite Road.
At many of the mountain passes there is a place to get out at the top with a restaurant.

In comparison this is the way you would drive to the Tre Cime, stopping off at Lake Prags
https://www.google.com/maps/dir/Auronzo+di+Cadore,+Province+of+Belluno,+Italy/Pragser+Wildsee,+Prags,+Province+of+Bolzano+-+South+Tyrol,+Italy/Innsbruck,+Austria/@46.9002578,11.5945764,10z/data=!3m1!4b1!4m20!4m19!1m5!1m1!1s0x4779ce97d875050f:0x407098715915320!2m2!1d12.3591123!2d46.5635366!1m5!1m1!1s0x47782f7e223aede7:0xbd2db4f14d5fc2f5!2m2!1d12.0854459!2d46.6946966!1m5!1m1!1s0x479d6ecfe1f8ca73:0x9d201c7d281d9b0d!2m2!1d11.4041024!2d47.2692124!3e0

The towns in Val Gardena are great places to stay and cute towns but not really that scenic. The towns have lifts to the mountains on all different sides to take you to scenic areas, hope that makes sense and why I was saying Val Gardena is not an attraction to stop at. If you want to see one of the nicer towns, stop on your way out in the town of Ortisei which is in the Val Gardena and has plenty of restaurants in town, part of the town is pedestrian only so may have to park and walk a little.
Ortisei is a very pretty town, extremely well kept with many of the buildings looking like doll houses.

While you technically can drive in certain hours on the Alpe Di Suisi in your situation the only option of seeing that is by taking a lift up to it from a town like Ortisei. I really don't think you have time for that unless you don't really do any hiking at Tre Cime. I believe at Tre Cime a decent amount of walking/hiking is needed for the best views so I am envisioning that as a 6 hour stop for you ; most people would do only that 1 stop in a full day and be tired after it too.

Well, after much deliberation, we decided to cancel the all-day Dolomite adventure and "just" have a free day around Innsbruck.

The Dolomites will still be there next time.

Thanks again to everyone. Your practical input was invaluable.

-Michael

IMHO you set in front of you a very difficult target. If you stay within easier limits a day trip into the Dolomites is well possible. Personally I have driven several times bewteen Innsbruck and Ortisei (something like 70 minutes); once you are in Ortisei, Passo Sella or Passo Gardena are within reach, and on a clear day they are some of the best places in Dolomites (on a bad weather day do yourself a favor and stay in Innsbruck). Getting more distant than that transforms the day trip into an odyssey.