With three weeks you can follow the whole southern arc: Lima, Arequipa and the Colca Canyon, Lake Titicaca, Cusco and Machu Picchu, then finish with three or four nights in the Amazon rainforest near Puerto Maldonado. The route runs from low to high and back down, ending at the warm, low end.
It is the first itinerary on this site that covers all three Peruvian worlds: coast, Andes and rainforest.
What three weeks buys
The 14-day route covers the coast, Arequipa and the Cusco region. Three weeks adds two more landscapes without losing the comfort: the high plateau around Lake Titicaca, and the Amazon basin. These are not extras to squeeze in; they change the character of the trip, from monuments and mountains to open water and rainforest.
The route avoids repeating the same transport pattern. It uses flights for the long legs, a scenic daytime bus or tourist train for the Arequipa, Puno and Cusco stretch if you want the views, and a short flight at the end for the jungle. The result is about seven bases in twenty-one nights, which too many cities treats as the upper limit of comfort.
Booking order for a three-week route
A longer trip has more fixed points, so the order of booking becomes a puzzle. Start from the Machu Picchu ticket and train, because they are the hardest to move, then place the other nights around them. Next come the flights into the south and out of the Amazon, then the Titicaca transfer, and last the lodges and hotels.
The rainforest lodge needs a decision early: lodges in the Tambopata area have fixed boat departures and package nights, so check what the stay includes. Reaching Puerto Maldonado from Cusco explains the flight and the transfer, and where to go in the Amazon helps you pick the gateway before you buy tickets. Keep a spare day before the international departure, since the Amazon flights are few.
Days 1 to 4: Lima and the first adjustment
Spend two nights in Lima, then fly to Arequipa, which is at moderate altitude. Day three is an unhurried Arequipa day, and day four is for the monastery and the market. Arequipa serves two purposes: it is a destination in its own right and it begins the adjustment.
For the main sights, see Arequipa; the Santa Catalina monastery is the one to put first because it is calm in the morning. Keep the evenings quiet, with a light dinner and water, and treat the second night as the real start of your altitude plan. The adjustment matters more on a long trip, because the highest nights come in the middle.
Days 5 to 7: Colca Canyon
Take a two-day trip to the Colca Canyon, with a night in a canyon village and an early visit to the condor viewpoint. Return to Arequipa on day seven for a night, or continue directly towards Puno with a bus or private transfer. Road conditions change with the weather, so keep the plan flexible.
The canyon villages are above 3,000 m, so this is the first real step up. For the tour formats, see Colca Canyon; tour or independent travel helps you decide whether to go with an agency. If you choose to continue to Puno directly, that makes day seven the longest travel day so far, so keep the evening empty.
Days 8 to 10: Puno and Lake Titicaca
Travel to Puno, which lies at about 3,800 m, higher than Cusco. The day is mostly the journey. On day nine take a boat to the Uros floating islands and the island of Taquile, usually combined into one day, or visit Sillustani by road in the afternoon. This section is deliberately slow: the lake is cold, the sun is strong and the air is thin.
Lake Titicaca compares the islands and the shore sites, and the Uros islands get an honest account of how brief and organised the visit can feel. If you prefer a quieter day, Sillustani and its stone burial towers are less crowded, and the wide, bare plateau around them is itself a reason to go.
Days 11 to 17: Cusco, the valley and Machu Picchu
Go from Puno to Cusco by the day bus with sightseeing stops, by a scenic tourist train where it is running, or by a short flight. Plan two nights in Cusco, then two in the Sacred Valley, one near Machu Picchu and a final night back in Cusco or the valley. By now you are adapted, so this is the right time for an optional Rainbow Mountain or Humantay lake day.
The sequence is a deliberate mirror of the short routes: you reach Machu Picchu after nine days of gradual altitude. Moving between Puno and Cusco compares the day bus, the train and the flight, and the Sacred Valley helps you choose the bases. A rest afternoon on day fifteen is worth planning, because this is the busiest stretch of the trip.
Days 18 to 21: the Amazon and home
Fly from Cusco to Puerto Maldonado and take a boat to a lodge in the Tambopata area. Two nights at the lodge are the minimum; three are better. The climate is hot and humid, the reverse of the Andes, and activities begin at dawn: wildlife walks, a clay lick, a night walk, a lake trip. Fly back to Lima through Cusco or directly, and use the last day only for the connection. Check with a travel clinic about the health precautions for the rainforest before departing.
If you want less jungle and more time elsewhere, drop to two nights and add the day to Lima. The Amazon itinerary goes into more detail on lodges, and health and vaccines gives general information to discuss with a doctor.
Frequently asked questions
Is three weeks too much travelling?
It is a lot of moves. The route uses five or six bases only, and each gets two nights or more, which keeps it manageable.
Can I skip Lake Titicaca?
Yes. Skip it and fly from Arequipa to Cusco, which saves about two days that can go to a longer Cusco stay.
Is the Amazon at the end a good idea?
Yes. It is low and warm, so it is a restful finish after the mountains, and it keeps the last days free of altitude.
How should I choose between the bus, train and flight from Puno to Cusco?
The day bus with stops is the best value and shows the scenery, the train is the most comfortable where it runs, and the flight saves a full day. Pick the flight if you are short of time or unwell.
Is a month better than three weeks?
Only if you want to add the north or a trek. The 30-day route spreads the same stops over more days and adds a different region.
What if the Amazon flight is cancelled?
Flights to Puerto Maldonado are few, so a cancellation can cost a day. That is why the route keeps the last day free and does not put a tight international connection next to the jungle stay.
Can I do the Amazon before Cusco instead?
You can, but the climb from the lowlands to Puno and Cusco afterwards is abrupt. Putting the jungle at the end keeps the altitude gradual and the last days easy.