Amazon River Cruises
A lot of amazon river cruises don't actually spend much time on the Amazon itself. Most usually are on tributaries where there is less commercial traffic and more wildlife.
In Brazil, some of the cruises will spend a little time on the Amazon, though I must clarify something about the name in Brazil. The Brazilians call it the Solimoes River until it merges with the Rio Negro River near Manaus. After that, they call it the Amazon. So, short cruises might spend all of their time on the Solimoes/Amazon and it's tributaries, while longer ones might spend some time there and the rest of their time on the Rio Negro and it's tributaries. There are other amazon cruises around Santarem, but not nearly as many as around Manaus.
In Peru, the original amazon cruises that started years ago did go from Iquitos down the Amazon River to the border with Brazil and Colombia, and then they would come back. But now, almost all amazon cruises head in the other direction, into the Pacaya-Samiria Reserve. So they spend a little time on the Amazon and when they get into the reserve, they go onto the Ucayali and/or Maranon Rivers and their tributaries. When these 2 rivers meet, they form what is generally considered as the Amazon River in Peru (though people will argue that the source of the Amazon is a stream far away in the mountains).
In Ecuador, there are 2 cruises that both operate the same itinerary on the Napo River, which is a tributary of the Amazon River. The 2 rivers meet east of Iquitos. These amazon river cruises offer a lot of cultural interaction as well as a good wildlife experience.
Those are the main countries for Amazon River cruises. In Bolivia there is a jungle cruise, but that is far from the Amazon River itself.
In Brazil, some of the cruises will spend a little time on the Amazon, though I must clarify something about the name in Brazil. The Brazilians call it the Solimoes River until it merges with the Rio Negro River near Manaus. After that, they call it the Amazon. So, short cruises might spend all of their time on the Solimoes/Amazon and it's tributaries, while longer ones might spend some time there and the rest of their time on the Rio Negro and it's tributaries. There are other amazon cruises around Santarem, but not nearly as many as around Manaus.
In Peru, the original amazon cruises that started years ago did go from Iquitos down the Amazon River to the border with Brazil and Colombia, and then they would come back. But now, almost all amazon cruises head in the other direction, into the Pacaya-Samiria Reserve. So they spend a little time on the Amazon and when they get into the reserve, they go onto the Ucayali and/or Maranon Rivers and their tributaries. When these 2 rivers meet, they form what is generally considered as the Amazon River in Peru (though people will argue that the source of the Amazon is a stream far away in the mountains).
In Ecuador, there are 2 cruises that both operate the same itinerary on the Napo River, which is a tributary of the Amazon River. The 2 rivers meet east of Iquitos. These amazon river cruises offer a lot of cultural interaction as well as a good wildlife experience.
Those are the main countries for Amazon River cruises. In Bolivia there is a jungle cruise, but that is far from the Amazon River itself.