This decision sets the tone for the whole trip and is often overlooked. Starting with high-altitude activities without prior acclimatization can lead to unnecessary fatigue and physical discomfort that end up affecting the rest of the itinerary.
During the first few days, it's best to prioritize gradual acclimatization. This process allows your body to adjust to the environment and better handle the pace of the following days. Choosing your first tours wisely not only improves the overall experience, it also reduces the likelihood of fatigue, headaches and altitude-related discomfort. To organize this order more clearly, the itinerary planner is a useful tool: it helps you arrange your tours in a logical sequence from the very start of your trip.
Why it's not a good idea to go to altitude on the first day
Arriving in town already means a significant change for your body: it sits at more than 2,400 meters above sea level, and that alone triggers an adaptation process, especially after long flights, late nights or little rest. Even if you feel good on arrival, your body has not yet adjusted to the lower oxygen availability.
Going higher on the first day usually combines several demanding factors at once. Tours such as Tatio Geyser, the Altiplanic Lagoons and Chaxa reach much higher elevations, and tackling them without acclimatization can lead to severe headaches, nausea, dizziness or marked fatigue, to the point of having to change or cancel later excursions. The body's response doesn't depend on age or fitness level: even active people can be affected if the ascent is too fast.
In addition, the reaction to altitude doesn't always appear right away. In many cases, symptoms show up during the night or the next day, when the body is already dealing with a demanding day. That's why the first day is best seen as an adjustment stage. San Pedro is best enjoyed when you respect its rhythm and let your body move at its own pace.
Ideal tours for arrival day
Arrival day works best with low-altitude tours, short outings and experiences that don't demand much physical effort. Rather than piling on activities, the idea is to start the trip with good balance.
The Valley of the Moon is a great choice for that first day. It's close to town, doesn't involve significant climbs and lets you explore striking landscapes without overtaxing your body. The afternoon slot is ideal: after the transfer and a short rest, the day ends with one of the desert's most famous sunsets.
He Rainbow Valley is also an excellent option for the first few days. Although it's farther from town, it sits at an altitude similar to San Pedro's (around 3,200 to 3,500 meters), so it doesn't demand extreme effort in terms of altitude. The tour combines short walks on flat terrain with stops offering unique views of multicolored hills. It's ideal for getting familiar with the desert and building acclimatization without overloading your body.
The Cejar Lagoon is another suitable option. It's a short tour, with well-paced timing and a low effort level. Floating in the lagoon and exploring the surroundings at a relaxed pace supports an initial adaptation without overloading your body.
The astronomical tour is also a good fit for the first day. It takes place at night, requires no strenuous walking or additional climbs, and takes advantage of one of the desert's great strengths: the clarity of its sky. It's an unhurried experience that complements the acclimatization process well. These tours share a similar approach: they don't involve high altitudes, avoid extremely early starts and let you enjoy the surroundings without unnecessary strain.
Which excursions to leave for later
Keep in mind that each excursion has a different physical impact. Some, while visually stunning, require prior adaptation to the altitude and desert climate. When they're scheduled too early, fatigue tends to set in sooner and the experience suffers. That's why higher-altitude, longer tours work best once you've spent one or two days in the destination and your body is more stable.
The Tatio Geyser is the clearest example. It is one of the most iconic tours in the desert and also one of the most demanding. It departs before dawn, temperatures are very low and the altitude exceeds 4,000 meters. Saving it for the third or fourth day usually makes a big difference: the cold is easier to handle, the effort feels lighter and you can enjoy the scenery at a more relaxed pace. The same goes for the Altiplanic Lagoons and Chaxa. These are long days, with several hours away and constant changes in altitude. When done without prior acclimatization, it's common to end the day exhausted or feeling unwell. With a few days to acclimatize, however, breathing is easier and your energy lasts throughout the entire tour.
With that in mind, waiting a day or two before the most demanding tours doesn't mean losing time. It means getting more out of every outing and experiencing the high-mountain excursions more fully and with more energy.
How does altitude influence the order of tours?
Altitude in San Pedro de Atacama shapes the pace of the trip. The body needs time to adapt to lower oxygen levels, and that adjustment happens gradually. That's why it's worth planning the order of tours around how your body responds to each altitude level. From the town itself, many tours climb several thousand meters in just a few hours. When that change happens abruptly, the sense of effort intensifies and fatigue sets in sooner. In those cases, it's not unusual for travelers to return with a headache or feeling they didn't fully enjoy the experience.
When the itinerary follows a more natural progression, the experience changes. Starting with lower-altitude excursions helps stabilize your breathing, improve your rest and build energy for the following days. From the second or third day on, going higher feels like a logical continuation of the trip. Altitude, then, doesn't limit the excursions available; it defines the best time to do them.
Example of a well-planned first and second day
A well-planned first day unfolds without rushing. Arriving, settling in, resting and choosing a low-intensity tour makes a clear difference. Valley of the Moon, Laguna Cejar or Rainbow Valley fit perfectly at this stage: they let you get moving, discover your surroundings and begin to adapt without pressure. The day ends on an active note, but with enough energy left to rest well. If you still have some energy, The Roofless makes an excellent finale. It adds no physical effort and offers an experience that truly captures the essence of the desert.
Day two allows you to slightly increase the intensity, always paying attention to how your body responds. Keeping to moderate-intensity tours helps consolidate acclimatization and prepares you for the more demanding tours. The key is to end the day feeling good.
With this order, excursions like the Tatio Geyser are well placed for the third or fourth day. You arrive feeling more confident, with better energy and the right frame of mind to enjoy them fully. When the trip is structured this way, everything flows more naturally. The experience gains depth and memories are made without rushing, something you'll notice from the very first day.
