Many travellers come to Leticia en route to Brazil or Peru. To get to the former, you need only head to the port of Tabatinga, just across the border, which has virtually fused with the Colombian town; there are no checkpoints between the two and all you have to do is walk south along Av Internacional.
Boats leave for Manaus from Tabatinga’s port on Wednesdays and Saturdays at around 2pm (double-check times in advance and remember that the time in Tabatinga is 1hr ahead of Leticia time), taking three days and four nights and costing around R$180 if you have your own hammock, or around R$1000 for a double cabin. The reverse journey (upstream) takes around six days and is more expensive.
High-speed passenger boats connect Leticia and Iquitos in Peru, leaving from Isla Santa Rosa; since the boats depart early in the morning, it’s easiest to stay in Tabatinga the night before, especially since in dry season boats can only cross over to Isla Santa Rosa from Tabatinga’s Porta de Feira. Boats depart daily around 4am (double-check departure times), with daily Transtur (973 412 2945, www.transtursa.com) services, while Transportes Golfinho (973 412 3186, www.transportegolfinho.com) leave Tabatinga on Tuesdays and Thursdays, coming back on Wednesdays and Sundays. Price includes breakfast and lunch. Don’t forget to get an exit stamp and relevant visa (see Visas in Brazil for additional information) before departing Leticia.