All foreigners must pay a COP$30,000 tourist tax upon arrival at Leticia's airport, Aeropuerto Internacional Alfredo Vásquez Cobo, to the north of the town.
Tabatinga International Airport has flights to Manaus daily. The airport is 4km south of Tabatinga; colectivos (shared taxis, minivans, or midsize buses) marked 'Comara' from Leticia will drop you nearby. Don't forget to get your Colombian exit stamp at Leticia's airport and, if needed, a Brazilian visa before departure.
When departing Leticia's airport, all foreigners must check in at Migración Colombia before proceeding through airport security, regardless of whether they're leaving Colombia or not; you'll be directed there after check-in if you haven't done it already – it's a painless and free procedure that takes a matter of seconds.
Buy tickets for Puerto Nariño and other points upriver at Transportes Fluviales. Boats to Puerto Nariño depart from Leticia's Amazon River dock at 8am, 10am and 1pm daily (COP$30,000, two hours). Arrive in good time for your boat, not least as the dock can be hard to find. You'll need your passport when buying your tickets.
If you're departing from Tabatinga (Brazil), be aware that it is one hour ahead of Leticia. Don't miss your boat!
Getting to Peru
High-speed passenger boats between Tabatinga and Iquitos (Peru) are operated by Transtur and Transportes Golfinho. Boats leave from Isla Santa Rosa daily around 5am except Monday, arriving in Iquitos about 10 hours later. Don't forget to get your Colombian exit stamp at the Leticia airport's Migración Colombia office the day before departure. (There is another office of Migración Colombia in town, but go there only for visa extensions and residency issues.) You can buy tickets through Selvaventura in Leticia, as neither company has an office in town.
The journey costs US$70 in either direction, including breakfast and lunch (mint-condition banknotes only; or COP$200,000). During dry season you can sometimes access Isla Santa Rosa only from Tabatinga's Porta da Feira, where water levels are always high. Check ahead. In fact, it's always easier in the middle of the night to go from Tabatinga, but taxi prices from Leticia can skyrocket to COP$30,000 for the ride.
Be warned: there are slower, cheaper boats to Iquitos, but they are not comfortable, are often unsafe and are best avoided.
Note there are no roads out of Iquitos into Peru. You have to fly or continue by river to Pucallpa (five to seven days), from where you can go overland to Lima.