These days, nearly all Amazon river cruises travel upstream from Iquitos to the confluence of the Ucayali and Marañon Rivers, and the Pacaya-Samiria Reserve. However, when I first took one of these cruises, in the year 2002, the Rio Amazonas took me and my group downstream to the tri-border with Colombia and Brazil. It remains a very interesting - albeit busier - river journey, which can be visited using local transport or by chartering your own vessel.
The Napo River’s headwaters are in Ecuador; this was the route that Francisco de Orellana used to descend the Amazon, from Quito, in 1541. It is the major Peruvian tributary into the Amazon, downriver from Iquitos.
Beyond this confluence is the village of Pevas (also called Pebas) about 90 miles (145 km) from Iquitos. Founded in 1735, this is the oldest town on the Peruvian Amazon and now has 3,000 inhabitants, the most famous of whom is the Peruvian artist, Francisco Grippa, who welcomes visitors to his home / studio / gallery which towers over the town.
Guests interested in his lively, jungle-themed paintings are served beer and bananas - in lieu of wine and cheese - by the friendly Grippa, who was born in coastal Tumbes, studied in the USA and Europe, but has made Pevas his home since the early 1990s.
Most of the town’s inhabitants are mestizos or natives of the four main local tribes, the Bora, Huitoto, Yagua, and Ocaina. Many of the villages in this region are home to small groups of one of these tribes, and are visited on tours arranged in Iquitos. They welcome tourists with dance performances, and accept both Peruvian and US currency in their craft markets!
Pevas is a regular stop for ships and boats traveling between Iquitos and the border, and has a couple of basic hotels.
At the tri-border with Colombia and Brazil, the biggest town is Colombian Leticia, with numerous hotels and daily flights to Bogota.
The town is connected (a short walk) with the smaller Brazilian port of Tabatinga, which has ships continuing down the Amazon taking about a week to Manaus, also reached by air from Tabatinga.
Ships from Leticia to Iquitos take about three days, while uncomfortable but fast rápido boats take about 12 hours. You will get your passport stamped at the Peruvian border post at Santa Rosa, which is across the river. Launches connect Santa Rosa with Leticia.