Most people plan Peru backwards. They book the flights, then the Machu Picchu tickets, then work out that Cusco sits at around 3,400 metres and that the first day may not go as planned. Altitude decides whether your second day is a walk around San Blas or an afternoon in a dark room with a headache.

This guide is for the traveller arriving in Cusco who wants the first three days to do a job: get you acclimatised without wasting the trip. It covers what altitude actually feels like, an arrival plan that works, which neighbourhood to sleep in, how to use the Sacred Valley as a stepping stone rather than a detour, and the Machu Picchu logistics that trip people up.

The core idea is simple. Cusco is high, the Sacred Valley is lower, and Machu Picchu is lower again. If you arrive at the top and work downwards, you suffer at the start. Go down first and come back up, and the whole trip feels different.

What altitude actually does in the first three days

Acclimatisation is not fitness. Being able to run a half marathon at sea level tells you little about how you will sleep at 3,400 metres. The body adapts by breathing faster and deeper at rest, which is why altitude feels odd rather than tiring: your heart rate is up while you are standing still.

What most people notice, roughly in this order:

• Breathlessness on stairs and slopes within a few hours of landing.
• A dull headache in the late afternoon or evening of day one.
• Broken sleep, waking up short of breath, and vivid dreams.
• Loss of appetite, mild nausea, and a strange indifference to food you would normally enjoy.
• Cold hands and feet, and a much stronger reaction to alcohol than usual.

None of that is unusual, and most of it eases over two or three days. What matters is not making it worse. The classic mistake is landing in the morning, dropping bags, and immediately walking a steep uphill itinerary because the flight was long and the trip is short.

Know the difference between uncomfortable and serious. Severe headache that will not shift, vomiting, confusion, breathlessness at rest or a cough that keeps getting worse are reasons to stop, descend and get medical help rather than to take another coca sweet. Decisions about preventive medication belong to a travel health professional, not to a blog post: talk to one before you fly, and confirm current guidance for the exact places and elevations on your route.

A three-day arrival plan built around acclimatisation

This plan assumes you land at Cusco and have three days before anything ambitious. It is deliberately dull. That is the point.

1. Day one: arrive and go down if you can. If your flight lands in the morning, transfer straight to the Sacred Valley — Urubamba or Ollantaytambo — rather than sleeping in Cusco, and spend the first night several hundred metres lower. If you are staying in Cusco, do almost nothing: check in, drink water, eat something light, and be asleep early.
2. Day two: gentle movement, no altitude gain. In the valley, this is a good day for Pisac’s market or the ruins above Ollantaytambo, taken slowly. In Cusco, walk the flat part of the centre around the Plaza de Armas, visit the San Pedro market, and skip anything with a staircase in the name.
3. Day three: gain a little height, or move up to Cusco. Travel back up to Cusco in the morning, stay the night, and see how you feel. If you have been in the valley, this is the first night that really tests you.
4. Day four onwards: the hard days. Machu Picchu, the Rainbow Mountain day trip or any trek belongs here, not before.

Practical habits that genuinely help:

• Drink more water than feels necessary, and keep sipping through the day rather than in one go.
• Eat lightly and often on day one. Soup, rice, bread and fruit are easier than a large meat-heavy meal.
• Skip alcohol for the first night or two. It hits harder and it disrupts the sleep you need.
• Take the stairs slowly and pause. Nobody in Cusco is watching you struggle; everyone has been there.
• Keep a layer handy. High-altitude sun burns and high-altitude shade chills, often within the same hour.
• Give yourself an easy afternoon each day; long daytime sleeps can make the first night worse.

The Rainbow Mountain day trip deserves a warning. It climbs to around 5,000 metres on a long, early-starting drive, and many people attempt it on day two because it looks like a single day out. Put any very high day late in the trip, not early, and be honest about turning back if you feel unwell on the way up.

Where to sleep in Cusco, and why the neighbourhood matters

In Cusco, elevation and gradient matter as much as room quality. Two hotels at the same price can feel completely different depending on whether the last five minutes of the walk home is flat or steep.

• Centro Histórico around the Plaza de Armas is the convenient choice: restaurants, tour offices on Avenida El Sol, and everything within a short walk. Noisy at night, and the walk down to the plaza is always easier than the walk back up.
• San Blas is the prettiest neighbourhood, full of small galleries and cafés, and it sits up a hill with stepped lanes. Wonderful once you are acclimatised; unpleasant on day one with a suitcase.
• San Pedro and the streets west of the centre are more local, cheaper, anchored by the market, and considerably flatter.

Two booking details matter more than any view. Ask whether the hotel has stairs to the rooms and whether anyone will carry your bag: a fourth-floor walk-up at altitude is a real cost. Ask about heating too, because Cusco nights are cold. Book the first two nights in advance and keep the rest flexible: check hotel availability for rooms with free cancellation.

The Sacred Valley: which town to use as your base

The Sacred Valley is not one place. It is a long, low ribbon of towns between Pisac and Ollantaytambo, most of it lower than Cusco, and the choice of base changes your whole trip.

A pattern that works well: two nights low in the valley, then two or three nights in Cusco, then Machu Picchu, then a final night in Cusco before flying out. It puts the altitude gain at the end of the acclimatisation, not the beginning.

Day trips from the valley fill the middle of the trip: the Maras salt pans and the terraces at Moray, the weaving villages around Chinchero, and the walk down to the ruins at Pisac. Organised day tours are the standard way to do these, since public transport between the smaller sites is slow and infrequent: see tour options. Skip the tour if you are basing yourself in Ollantaytambo and are happy to use colectivos; the ruins there are on the edge of town and need no guide at all.

Getting to Machu Picchu without wrecking yourself

Machu Picchu sits lower than Cusco, at roughly 2,400 metres, which is one of the reasons it feels fine to visit on day five or six and dreadful on day two.

The standard route is train to Aguas Calientes, then a bus up to the site. Trains leave from Ollantaytambo for most of the day and from Poroy, nearer Cusco, on a more limited schedule — so many travellers spend the night before in Ollantaytambo and take an early train. Confirm current timetables and luggage rules before you go, because both change.

Things that catch people out:

• Entry is timed and ticketed, and the ticket includes a specific circuit. Buy from the official ticketing channel rather than a reseller, and check which circuit your ticket covers before you plan your day. Confirm the current rules, because the circuits and time slots are revised from time to time.
• Huayna Picchu and Machu Picchu Mountain need separate permits with limited daily numbers, released on a published schedule and often gone months ahead. If either matters to you, this is the first thing to book, before flights.
• The classic Inca Trail closes for annual maintenance in February, and permits for the rest of the year are limited and released in advance. Confirm current season dates and permit rules before you build a trip around it.
• Aguas Calientes is small, and entry needs your passport. Book accommodation as early as the trains, and bring the same document you booked with.

For most travellers, the honest recommendation is a train-and-bus day rather than a trek if you have limited time or are unsure about your altitude response. Treks are wonderful and they are also the thing that most often turns into a miserable experience when the acclimatisation days were skipped.

Practicalities: water, weather, money and insurance

Water and food. Do not drink tap water. Bottled water is everywhere, refill stations exist in Cusco and Ollantaytambo, and the market at San Pedro is the best cheap eating in the city — quinoa soup, grilled trout, tamales and fresh juice. Eat lightly on arrival and build up. Coca tea is part of how the region handles the height; it is not a substitute for descending if you feel genuinely unwell.

Weather. The dry season runs roughly from May to September and is the busiest window. The wet season brings afternoon rain, greener hills and fewer people. In either season you want a waterproof layer and something to keep electronics dry: on a wet day at Machu Picchu, a roll-top dry sack is the simplest insurance for a phone and passport. Based on published specifications, the Sea to Summit Ultra-Sil Dry Sack is light enough to carry every day and doubles as a laundry bag — check current price at REI. Skip it if you are travelling in the dry season with a waterproof day bag; the weight is small but it is not free.

Money. Carry soles in cash for markets, colectivos and small restaurants, and use ATMs in Cusco rather than the valley towns. Cards work in mid-range and upmarket hotels and restaurants. Keep a backup card separate from your main one.

Insurance matters more here than on most trips. Altitude illness, trekking above certain elevations and helicopter evacuation are the things policies treat differently, and the exclusions are where the detail lives. Read the wording for the heights and activities on your itinerary, and if trekking is central to the trip, check that it is covered rather than assumed: our guide to whether you need travel insurance walks through how to judge a policy. Arriving in Cusco by land rather than by air is slower but far lower-carbon, and the reasoning in the choices that actually cut emissions applies neatly here.

Frequently asked questions

How many days do you need in Cusco before Machu Picchu?

Three full days is a sensible minimum if you are flying in from sea level, and four is better: one very easy day, one moderate day, then a night back at Cusco altitude before the trip to the site. If you go straight to the Sacred Valley on arrival, you can compress this slightly.

Is it better to stay in the Sacred Valley or Cusco first?

The Sacred Valley first is easier on the body, especially after a long flight: Urubamba and Ollantaytambo are several hundred metres lower than Cusco, and the transfer down is straightforward. Staying in Cusco first is more convenient for tours and restaurants, and harder physically.

Does coca tea actually help with altitude?

Coca tea is the local habit and many travellers find it soothing, partly because drinking warm fluid regularly helps at altitude. It is not a treatment for altitude sickness and will not fix a severe headache or breathlessness at rest. If symptoms are getting worse, the answer is to descend and seek medical help.

What should you pack for Cusco and the Sacred Valley?

Layers, a waterproof shell, sun protection, a refillable bottle, cash in small notes and comfortable shoes for cobbles and steps. Add a light dry bag if you are travelling in the wet season or doing any trekking. And pack less than you think: moving between altitude and lower towns with a heavy bag is the fastest way to make a hard day harder, which is the whole argument in our one-bag packing list.

The bottom line

Treat altitude as a scheduling problem rather than a test of character. Land, go low, sleep, drink water, eat lightly, and only then start climbing the itinerary. Put Machu Picchu on day five or later, give yourself one flat day in the middle, and book the fixed pieces — trains, entry tickets, permits — as early as their release windows allow.

The travellers who have a bad time in Cusco are almost never the unfit ones. They are the ones who landed at breakfast, walked the city all afternoon, ordered a large dinner with wine, and spent day two in bed wondering what went wrong.