There are showers and thunderstorms throughout the year, hence waterproof bags and/or containers will be important to protect things as documents, cameras and, significant articles. Fresh cotton clothes, long sleeves, long pants, mosquito repellent, and a flashlight are necessary too, especially for trekking in the depths of the rainforest. It is also possible to consider bringing a sun block, sunglasses, a lighter, and a pocket knife. A raincoat, a mosquito net and rainboots (wellies) are a good idea but are not essential.
Curassow Amazon Lodge provides rubber boots for expeditions in the jungle and awesome facilities to rest after excursions. Also, some lodgings include free baggage storage as the Emperador Terraza Hotel in Iquitos.