Most visitors come to see the falls, and rightly so, but try to arrive early to avoid the crush of tour buses from Puerto Iguazú  and Brazil. The sole exception to thw Disneyland entry hours are the monthly full-moon hikes, guided by park rangers.
Visitors pay the entrance fee at the Portal Cataratas, the gate to the slickly managed complex of fast-food restaurants, souvenir stands, and tour operators. The most worthwhile sight here is the park service’s Centro de Interpretación.
Traditionally, park visitors walk along three major circuits on mostly paved trails and pasarelas (catwalks) that zigzag among the islands and outcrops to make their way to overlooks of the falls. The Circuito Superior (Upper Circuit) is a 650-meter route with the best panoramas of the Argentine side of the falls, while the 1,700-meter Circuito Inferior (Lower Circuit) offers better views of individual falls and also provides launch access to Isla San Martín for exceptional perspectives on the amphitheatrical Garganta del Diablo (Devil’s Throat), Iguazú ’s single most breathtaking cataract.
Most visitors take the Tren de la Selva, the narrow-gauge railway, to reach the trailhead for the 1,130-meter catwalk to the overlook for the Garganta del Diablo; this means an unavoidable soaking while watching the vencejo de tormenta (ashy-tailed swift) dart through the booming waters to and from nesting sites beneath the falls. The view almost defies description, though the spray can obscure the base of the falls and even on the hottest days can chill sightseers—bring light raingear, plastic bags to protect cameras and other valuables, and perhaps even a small towel.
Far fewer visitors explore forest trails than the pasarelas, except for the 20-minute Sendero Verde, a short forest walk leading to a small wetland that’s home to birds and butterflies. The six-kilometer Sendero Macuco, a nature trail that starts near the train station, is the likeliest place to spot or hear the tufted capuchin monkey. Mostly level, it drops to the Salto Arrechea, a small waterfall, via a steep, muddy, and slippery segment. Mosquito repellent is desirable.