Leticia is a town of about 33,000 on the Amazon with no road connecting it to the rest of Colombia — you fly in, and everything you came for is upriver, downriver or across a border.
Puerto Nariño and Lago Tarapoto
A car-free river town roughly two hours upstream by fast boat, and the base for Lago Tarapoto where pink and grey river dolphins are regularly seen. Boats leave Leticia's muelle in the morning; a day trip is possible but staying a night gets you the dawn and dusk, which is when anything happens.
Parque Nacional Natural Amacayacu
267,241 hectares of rainforest reached via Puerto Nariño and then the Mocagua or San Martín de Amacayacu communities, who run the ecotourism themselves. Entry is 73,000 COP for foreign non-residents and 27,500 for Colombian adults, staff are on 8am to 4pm, and you book through the community offices rather than a park gate.
Mundo Amazónico
A private reserve just outside town built around four short routes: a medicinal-plant botanical garden, an aquarium of native Amazon fish, a forest trail and a cultural section. The basic four-route visit is 100,000 COP, an English-speaking guide adds 90,000, and children aged 4–11 get 20% off the routes.
Reserva Natural Tanimboca
A reserve outside Leticia running canopy platforms, night walks, birdwatching and cabins built up in the trees, booked from an office at Calle 12 #10-97 in town. Trips range from an easy half day to multi-day bushcraft and survival routes deeper into the forest, and they are built around what you want rather than fixed packages.
The three-border crossing
Leticia runs straight into Tabatinga in Brazil with no checkpoint on the street between them, and Santa Rosa in Peru is a short boat ride across the water. Wandering between countries is an ordinary daily thing here, but if you are travelling onward into Brazil or Peru you must get stamped at the proper immigration offices first.