There are scores of tour operators who will offer to take you up the Rio Solimões, the Rio Negro, and its tributaries. Some will even take you on both. Most people go on excursions that last 2–4 days, but it’s possible to find 1–2 week excursions that journey into very remote areas. Long before you get to Manaus, it’s best to do some research and check out tour companies’ websites in advance.

Take a look at the boats and accommodations available and make sure guides speak English and have some knowledge of the jungle. If in doubt, also check the company’s credentials with Amazonastur (Rua Saldanha Marinho 321, Centro, tel. 92/2123-3800, www.amazonastur.am.gov.br, 9 a.m.–6 p.m. Mon.–Fri.), the state tourist bureau.

Ecotourism has become a big business, and the minute you get to Manaus you’ll be accosted at the airport, rodoviária, and/or ports by locals offering excursions. Just give them a firm, but polite “Não, obrigado/a.” Even if they flash a brochure from a reputed agency (such as those listed here) refuse—there have been reports of scammers impersonating legitimate operators.

Before you fork out any money, get in writing everything that’s included in the price of your excursion. Usually a decent budget excursion will cost R$150–200 per day while a more specialized excursion with more upscale accommodations will set you back R$250–400 a day.

Amazon Gero’s Tours (Rua Dez de Julho 679, Sala 2, Centro, tel. 92/9983-6273, www.amazongerotours.com) is run by experienced and friendly English-speaking guide Geraldo (“Gero”) Mesquita. Gero customizes reasonably priced tours throughout the region, especially along Rio Solimões around the areas of Lago Mamori and Lago Juma (Gero owns his own jungle lodge, the Ararinha Jungle Hotel, in the region). Accommodations can be on boats, in jungle lodges, in hammocks, or even with local families in villages.

Also highly recommended is Swallows and Amazons (Rua Quintino Bocaiúva 189, Centro, Sala 13, tel. 92/3622-1246, www.swallowsandamaazontours.com), a small company owned by American Mark Aitchison and his Brazilian wife, Tania, that custom designs topnotch riverboat, jungle lodge, and adventure tours for small groups that usually last for a week or more. Swallows and Amazons organizes trips along the still wild and unspoiled upper Rio Negro, including the Arquipélago Anavilhanas (close to which lies its own floating jungle lodge, the Araras Lodge). The all-inclusive excursions cater to various interests and can include activities such as diving, bird-watching, fishing, as canoeing as well as stays with caboclo families.

For completely off-the-beaten-track and into-the-Heart of Darkness jungle tours you’ve always fantasized about, Amazon Mystery Tours (Rua Brasil 27, Redenção, tel. 92/3228-3733, www.amazon-outdoor.com) specializes in trips to remote tributaries and private reserves to which it has exclusive access. Those who want a back-to-nature experience can stay in tents, while others seeking creature comforts can bunk aboard a posh yacht. Among the activities Amazon Mystery offers are kayaking and tree climbing into the lofty heights of the rainforest’s upper canopy—a truly amazing experience.

For budget travelers, Amazonas Indian Turismo (Rua dos Andradas 311, Centro, tel. 92/3622-0204) is a long-standing operator that offers good basic tours led by Amazonian Indians (most of whom speak English). Groups are small and, as such, can be personalized. For longer getaways into the depths of the jungle, the company has its own very rustic camp with hammocks and outhouses on the Rio Urubú, 200 kilometers (124 miles) from Manaus.