As the largest salt flat in the world, the Salar of Uyuni is the main draw of Bolivia and its pĂece-de-resistance for most international visitors. Touring Uyuni is also the most expensive thing Bolivia will throw at you, so you need to have a game before you arrive.
I would have done a lot of things in Uyuni differently had I known before what I know now. Read on to avoid making the same mistakes I did.
Choosing a Tour: One Day vs. Three Day Tour

Regardless of what company you choose, you will visit the exact same attractions. The main thing you need to decide is whether you want a 1-day tour or a 3-day tour. I should note the 3-day tour is really a 2-day tour since almost all of the 3rd day is spent in riding back to Uyuni (or across the border to San Pedro if you so choose).
The one day tour is the same as the first day of three day tour and contains all of the most important attractions including the salt flat, perspective photos, the fisher island (Incahuasi) and the mirror.
The cheapest three day tour is more than triple the price of 1-day tour , but I personally chose this option because it ends near the Chilean border, which is where I was headed to after Uyuni.
Other than that, the main advantage of the three day tour is that you see some colored lakes on the second day and some geysers in the eMarly morning of the third day. Neither of these was very impressive. Most of the photos I saw online of these lakes had been heavily edited to make them seem much more colorful than they really are, so I was a bit dissappointed

Choosing a Tour Operator

THIS IS SO IMPORTANT! Do not choose a tour operator blindly. When I arrived in Uyuni, a tour operator snagged me off the bus and pressured me to book with her without giving me time to think or look up reviews. This was a terrible mistake because that tour operator was corrupt, unethical, and dishonest. Everyone wanted to murder her by the end of the tour.
Before you arrive, you should read reviews online for different operators and map out where the operator you have chosen is located. Alternatively, you can ask other travelers who have been to Uyuni for a recommendation. Whatever you do, do not book with any of the agencies by the bus terminal and avoid the heap of shit that is Laura Travel like the plague.
Costs

The cheapest one day tour costs 150 BP while the cheapest three day tour costs 650 BP. This includes meals and two nights of accommodations. It does not include the 30 BP entrance fee for Incahuasi (“fisher island”), which you visit on the first day, nor the 150 BP entrance fee for National Park, which you visit on the second day.
If you want a hot shower on the second night, that’s an additional 15 BP. The morning of the third day, you’ll visit thermal baths, which costs 6 BP if you choose to enter. Those who opt for the transfer to San Pedro de Atacama in Chile at the end of their tour can expect to pay an additional 70 BP for the transfer.
What You See on the Tour
Day 1
The first stop of the tour is the train cemetery just on the outskirts of Uyuni town. This is the final resting place of all the discontinued freight lines that once ran through Uyuni.

The train cemetery is mobbed with tourists in the morning because all the tours arrive here at the same time, so you’d be well advised to visit independently the day before your tour begins if you want to get a photo of it when it

Next you will have two small stops on your way to lunch at the salt hotel. The first is a touristy village in the desert called Colchan where you can buy salt souvenirs. The second is a patch of bubbling puddles on the edge of the salt flat called the Ojos del Salar (eyes of the salt flat).

Then you’re off to have lunch at the Salt Hotel. You’ll have a half hour to take pictures with the flags outside the hotel left from the 2014 Dakar Rally while your guide prepares your lunch. You’ll lunch inside the salt hotel’s dining area and have some free time afterwards to explore inside the hotel.

On the way to your next stop, you’ll pull over to take silly perspective photos. If you booked a descent tour, your guide will know how to take the best photos and will provide a dinosaur for the occasion. Our underpaid and inexperienced guide botched all the photos he took for our group, so a few of us went off to improvise our own photos.

Next is Incahausi, a rocky cactus-covered outcrop sticking out from the middle of the salt flat. You must pay 30 BS to climb it, so our whole group just loitered around it until it was time to ago.

A reflective flooded section of the salar called the espejo (“mirror”) was the last thing we visited on day one, but your operator may skip if it if you haven’t asked for it ahead of time. Sunset in particular is the best time to take photos at the espejo.
If you book a respectable tour, you will be provided with boots so you can walk about freely without destroying your shoes. Our tour operator had no such consideration, so most of our group just sat in the car and missed out. My shoes were completely ruined after visiting this, so make sure to check BEFORE YOUR TOUR that your operator will be providing boots.
Day 2
The second day is mostly about visiting a series of sulfurous lakes near the Chilean border

You’ll pass these volcanic rocks on your way to the lakes, including the formation above, which is supposed to resemble an eagle.

After a few hours, you reach the first lake, which look likes a field of white because it’s covered in sulfur.

The second lake is not much different. You may see flamingos.

The third lake is blue. More flamingos.

The fourth lake is overkill. Who really wants to see so many lakes?

The lake parade in briefly interrupted by the arbol de piedra (“stone tree”).

The grand finale for the lakes is the Laguna Colorada. You have to pay an obligatory 150 BP national park fee before you can get there.
The lake is not nearly as colorful as edited photos will have you think. It’s blue with green patch from algae, some white patches from sulfur (like the previous lakes), and a bit of a brackish red-brown in some spots from another type of algae.
That night you’ll sleep in a small town near the lake. If your hostel has hot showers, Wifi, or electricity, it will charge extra to make use of them.
Day 3
You will leave the hostel at 5:00 AM on day 3 to see the geysers, which are very crowded in the morning. Then, you go to some thermal baths.

After the thermal baths, you drive an hour to see a green lake near the Chilean border that looks like any other lake. By 10 AM, those who are transferring to San Pedro de Atacama, Chile will be dropped off at the border, and the rest will spend 7 hours in the van headed back to Uyuni.
Is the three day tour worth it?
The main difference between one day tour and three day tour are the series of lakes. Does the idea of seeing a bunch of vaguely discolored lakes excite you so much you would pay more than triple the price for a tour that includes them? No? Maybe you better stick to a one day tour then.
The third day of the three day tour is so short that you might as well think of it as a two day tour. Even though the three day tour helped me get to Chile, in retrospect, I would have preferred to save my money and reach Chile independently. The sights on day two and day three really were not that interesting to me.
To review, make sure your tour operator:
- has a good reputation
- agrees to take you to the espejo (mirror)
- will provide boots for the espejo