Getting from Brazil to Peru by boat?

I'm planning on going travelling in South America early next year. The main plan is to fly into Rio then head up the amazon on a river boat from Manaus to Iquitos in Peru. Is this boat trip possible? Any idea how long it would take and how much it would cost? Has anyone done this before? I'd love to hear about some of thier experiences.

Yes, of course this is possible easily. I did it around 10 years ago in the opposite direction (to Manaus only). So cruising against the current will double the trip time more or less. I started in Yurimaguas -> 3 days to Iquitos -> 3 days to Manaus.

The trip from Yurimaguas (on Rio Ucayali) was 25 US$, incl. meals (which were uneatable, we provisioned ourselves). Sleeping in a hammock on the upper deck, as all the Peruvians. There were some tiny cabins on one end of the boat (MS Eduardo II, 200 - 400 passengers and cargo) but in the heat an open space is much more convenient. It was crowded but people were very nice and we made a lot of friends.

The trip on Amazonas further to Manaus was much more luxurious. Around 70 US$. I don't know if these boats still operate or if they have been replaced. They were quite old when we traveled. But I'm sure that these connections still exist and probably have improved as the relations between Peru and Brasil have improved as well.

Aloha, Thomas

PS: You find a lot of infos in google typing 'ucayali' and also 'uyacali' which actually is written wrong.

Yes it's possible if you have plenty of time. There is no direct boats. First you have to go to Banjamin Constant, there you'll find boats going to Ramon Castilla in Peru, then there you'll follow your route up to Iquitos with another boat.