Is Cusco or La Paz higher?

La Paz, and by more than people expect. Cusco sits at 3,399 m and the city of La Paz at about 3,640 m, with its airport at El Alto higher still at 4,061 m. The practical difference is the arrival: from Cusco you can descend to the Sacred Valley at 2,871 m to sleep, and from El Alto most itineraries do not descend at all.

Does being fit protect you from altitude sickness?

No. The CDC is explicit that training and physical fitness do not affect the risk. Nor does being young: people over fifty are at slightly lower risk, not higher. The only things that reliably help are the rate at which you gain sleeping altitude and, for some travellers, medication prescribed by a doctor.

How many days do you need to acclimatise before Machu Picchu?

Fewer than most itineraries assume, because Machu Picchu is the low part of the trip. The citadel sits at 2,430 m, below the 2,450 m threshold at which the CDC considers an unacclimatised traveller at risk at all. The altitude problem in Peru is Cusco at 3,399 m, not the ruins, which is why we sleep in the Sacred Valley first.

Is it safe to fly straight into La Paz?

It is common and it is not forbidden, but it puts you in what the CDC calls a high-risk category: destinations reached by rapid ascent above about 3,400 m, where reported rates of altitude illness approach half of arrivals. The CDC's own suggestion for La Paz is to sleep one or two nights lower than the airport before going up.

What percentage of people get altitude sickness in Cusco?

About 40%. In a 2012 to 2016 cohort of young, healthy travellers arriving in Cusco, two in five developed acute mountain sickness, and drinking coca tea was not associated with lower risk. Sleeping the first nights lower, in the Sacred Valley at around 2,800 m, is the usual way to reduce it.

Will I get altitude sickness in Bolivia?

You might, and the route decides how likely. Flying into La Paz lands you at El Alto airport, 4,061 m, and the CDC puts rates approaching 50% for travellers sleeping above 3,400 m on their first night. Arriving overland from Peru after nights at Lake Titicaca means you gain height in steps. Fitness does not protect you; the pace at which your sleeping altitude rises does.

What are the symptoms of mild altitude sickness?

A headache, plus one or more of nausea, tiredness, dizziness or poor sleep. Symptoms usually start 2 to 12 hours after arrival and settle within 12 to 48 hours if you stop gaining altitude. Do not sleep any higher while you have them, however mild; descending 300 m or more usually brings quick relief.

Should I take altitude sickness pills like Diamox for Cusco?

Ask a travel-medicine doctor before you fly. The CDC documents acetazolamide, sold as Diamox, at 125 mg every twelve hours, started the day before ascent, as shortening acclimatisation, and in the Cusco cohort taking it was associated with lower risk. It is not right for everyone, and it works alongside a route that sleeps low first, not instead of one.

South America · Travel guide

South America Altitude: 12 Elevations and How to Plan

Reviewed by Pedro Toaquiza, founder and bilingual tour guideUpdated 5 October 2026

South America altitude, verified: Cusco 3,399 m, Machu Picchu 2,430 m, La Paz airport 4,061 m, and why the order of your route beats any pill.

This is the reasoning we use when we date a trip, not an article written to fill a blog. The itineraries it feeds are here.

A glacial lake below a snow-covered peak high in the Peruvian Andes — Photo by Simon P. Toaquiza.

Most altitude trouble on a Peru and Bolivia trip is a scheduling problem, not a medical one. You leave Lima at sea level and stand in Cusco at 3,399 m ninety minutes later. Your body gets no vote. In a cohort of young, healthy travellers arriving in Cusco, two in five developed acute mountain sickness. Fly into La Paz instead and you land at El Alto, 4,061 m, one of the highest international airports in the world.

The altitudes are fixed. The order in which you meet them is not. That is the part you control, and it changes the trip more than anything you can buy in a pharmacy.

The elevations, in one table

Place	Country	Metres	Feet	Note
Aguas Calientes	Peru	2,040	6,690	Where you sleep for an early entry
Arequipa	Peru	~2,300	~7,550	Common first Andean stop
Machu Picchu citadel	Peru	2,430	7,970	Almost 1,000 m below Cusco
Quito	Ecuador	2,850	9,350
Cusco	Peru	3,399	11,152	Airport arrival from sea level
Salar de Uyuni	Bolivia	3,656	11,995
La Paz	Bolivia	~3,650	~11,975	Centre 3,600 m, Zona Sur 3,250 m
Uyuni town	Bolivia	~3,700	~12,139	Where the 4x4 circuits start
Lake Titicaca	Peru and Bolivia	3,812	12,507
Puno	Peru	3,830	12,570	Higher than the lake it sits on
El Alto	Bolivia	~4,000	~13,123	Reaches 4,300 m
El Alto airport	Bolivia	4,061	13,325	One of the highest international airports
Potosí	Bolivia	4,067	13,343

Read that table next to your flight times, not on its own. Cusco and La Paz are both airport arrivals, and both put you above 3,400 m on your first night, which is the threshold the CDC uses to define its high-risk category.

Cusco altitude: 3,399 m, from sea level in ninety minutes

Cusco altitude is 3,399 m, or 11,152 ft, and almost everyone arrives the same way: a short flight from Lima, which sits at sea level. That is the whole problem. Cusco elevation is not extreme by Andean standards, lower than La Paz, Puno or the Salar de Uyuni, but no other stop on a Peru trip asks your body to climb so far so fast.

The measured result is the 40% figure above: two in five healthy travellers arriving in Cusco developed acute mountain sickness. Most of them felt it in the first two days, which on a standard itinerary are the days set aside for the city tour.

The fix is not to avoid Cusco, it is to postpone sleeping in it. Land, drive down to the Sacred Valley at around 2,800 m, spend two nights there, and come back up to the city once you have had time to adjust. The walking tour of Cusco is the same tour on day four as on day one; the way you feel during it is not.

Machu Picchu elevation: 2,430 m, the low part of the trip

Machu Picchu elevation is 2,430 m, or 7,970 ft, according to UNESCO’s listing for the Historic Sanctuary. Aguas Calientes, the town where you sleep for an early entry, sits lower still at 2,040 m. Both are almost 1,000 m below Cusco.

That number answers the question most people are really asking when they search for Machu Picchu altitude: whether the ruins themselves will make them ill. For most travellers they will not. The citadel is just under the 2,450 m at which the CDC starts counting unacclimatised travellers as at risk. If you feel the altitude on the day you visit, it is almost always the night you spent in Cusco beforehand, not the climb to the terraces.

It also changes the order. Doing Machu Picchu early, between the Sacred Valley and Cusco, puts the lowest and most famous day of the trip where your body needs a break, and leaves the high city for when you are ready for it.

Where the risk actually begins

Unacclimatised travellers start being at risk from about 2,450 m. At roughly 3,050 m, the partial pressure of the oxygen you breathe is only 69% of what it is at sea level. That is not a metaphor, it is the whole mechanism.

Acute mountain sickness is the common form: headache, plus nausea, tiredness, dizziness or poor sleep. It affects about 25% of visitors sleeping above 2,450 m in Colorado. Symptoms usually start 2 to 12 hours after arrival and settle within 12 to 48 hours if you stop climbing.

The two severe forms are rarer. High-altitude cerebral edema is uncommon below 4,300 m. High-altitude pulmonary edema runs at roughly one case per 10,000 Colorado skiers, and up to one in a hundred travellers above 4,300 m.

How common it is at the altitudes you will sleep at

This is where travel-blog numbers and measured numbers separate.

Cusco arrivals: about 40% developed acute mountain sickness in a 2012 to 2016 cohort.
Flying to 3,740 m: 84%, in a 2023 review of published studies.
Walking up to between 2,850 m and 4,559 m: 9% to 52%, depending on the altitude.
Sleeping above 3,400 m on day one: the CDC puts rates “approaching 50%”.

Why the plane is the problem

A 2023 review in the Journal of Travel Medicine compared twelve observational studies covering 11,021 people at nineteen different altitudes. Altitude sickness rose 4.5 times more steeply per 100 m gained when people arrived by air than when they arrived on foot or overland.

That single ratio is the argument for building an itinerary the long way round.

How long acclimatisation takes

The first and largest adjustment happens over three to five days at a given altitude. You cannot compress it. The published ascent rules are simple:

Do not go from below 1,200 m to sleeping above 2,750 m in one day.
Above 3,000 m, move your sleeping altitude by no more than 500 m a day.
Add a rest day for every 1,000 m of sleeping altitude gained.
Descending 300 m or more usually relieves symptoms quickly.
Never sleep higher than the night before while you have symptoms, however mild.

Every rule is about sleeping altitude. Going up for the day and coming down to sleep is a different thing from moving your bed up the mountain.

What the evidence supports, and what it does not

The CDC documents acetazolamide at 125 mg every twelve hours, started the day before ascent, as shortening acclimatisation. Dexamethasone relieves moderate to severe symptoms faster. Ibuprofen helps prevent them, though less well. Descent and oxygen treat them.

Coca tea is the thing every visitor is offered. In the Cusco cohort, drinking it was not associated with lower risk. Taking acetazolamide in the same study was. Coca is part of the place and worth trying. It is not a plan.

This section describes what the published literature says. It is not medical advice, and none of these drugs is right for everyone. Take the list to a travel-medicine doctor before you fly.

The order of cities beats any pill

Compare two ways of reaching the same three highlights.

The fast one. Lima, fly to Cusco on day one, Machu Picchu, fly to La Paz. Two sea-level-to-high-altitude jumps in one trip, both into the high-risk band.

The one we build. Lima, Arequipa, then Puno, then overland across the altiplano into La Paz, ending in Uyuni. You gain altitude in steps and you sleep at each step. Same places, different physiology.

The second costs you two or three days. The first can cost you the first three days anyway, spent in a hotel room.

The trick nobody tells you about Cusco and La Paz

The CDC names both cities directly: travellers can descend below the airport to sleep for a night or two, then begin their ascent.

In practice that means landing in Cusco and driving straight down to the Sacred Valley, around 2,800 m, before you ever sleep in the city. In La Paz it means booking the Zona Sur at about 3,250 m rather than the centre at 3,600 m.

It also means doing Machu Picchu early. The citadel is at 2,430 m and Aguas Calientes at 2,040 m, both comfortably below Cusco. The famous part of the trip is the low part.

Who should talk to a doctor first

Children are as susceptible as adults. People over fifty have slightly less risk, not more. Anyone with a previous episode of pulmonary or cerebral edema is in the high-risk category regardless of how they ascend.

If you have heart or lung disease, sickle cell trait, or you have had altitude illness before, get a consultation before you book the flights. It may change the route, and the route is the cheapest thing to change.

Asked before booking

The questions we get on this

Is Cusco or La Paz higher?: La Paz, and by more than people expect. Cusco sits at 3,399 m and the city of La Paz at about 3,640 m, with its airport at El Alto higher still at 4,061 m. The practical difference is the arrival: from Cusco you can descend to the Sacred Valley at 2,871 m to sleep, and from El Alto most itineraries do not descend at all.
Does being fit protect you from altitude sickness?: No. The CDC is explicit that training and physical fitness do not affect the risk. Nor does being young: people over fifty are at slightly lower risk, not higher. The only things that reliably help are the rate at which you gain sleeping altitude and, for some travellers, medication prescribed by a doctor.
How many days do you need to acclimatise before Machu Picchu?: Fewer than most itineraries assume, because Machu Picchu is the low part of the trip. The citadel sits at 2,430 m, below the 2,450 m threshold at which the CDC considers an unacclimatised traveller at risk at all. The altitude problem in Peru is Cusco at 3,399 m, not the ruins, which is why we sleep in the Sacred Valley first.
Is it safe to fly straight into La Paz?: It is common and it is not forbidden, but it puts you in what the CDC calls a high-risk category: destinations reached by rapid ascent above about 3,400 m, where reported rates of altitude illness approach half of arrivals. The CDC's own suggestion for La Paz is to sleep one or two nights lower than the airport before going up.
What percentage of people get altitude sickness in Cusco?: About 40%. In a 2012 to 2016 cohort of young, healthy travellers arriving in Cusco, two in five developed acute mountain sickness, and drinking coca tea was not associated with lower risk. Sleeping the first nights lower, in the Sacred Valley at around 2,800 m, is the usual way to reduce it.
Will I get altitude sickness in Bolivia?: You might, and the route decides how likely. Flying into La Paz lands you at El Alto airport, 4,061 m, and the CDC puts rates approaching 50% for travellers sleeping above 3,400 m on their first night. Arriving overland from Peru after nights at Lake Titicaca means you gain height in steps. Fitness does not protect you; the pace at which your sleeping altitude rises does.
What are the symptoms of mild altitude sickness?: A headache, plus one or more of nausea, tiredness, dizziness or poor sleep. Symptoms usually start 2 to 12 hours after arrival and settle within 12 to 48 hours if you stop gaining altitude. Do not sleep any higher while you have them, however mild; descending 300 m or more usually brings quick relief.
Should I take altitude sickness pills like Diamox for Cusco?: Ask a travel-medicine doctor before you fly. The CDC documents acetazolamide, sold as Diamox, at 125 mg every twelve hours, started the day before ascent, as shortening acclimatisation, and in the Cusco cohort taking it was associated with lower risk. It is not right for everyone, and it works alongside a route that sleeps low first, not instead of one.