The falls may be reached from two main towns, with one on either side of the falls: *Foz do Iguaçu (map) in Brazil and *Puerto Iguazú (map) in Argentina, as well as from *Ciudad del Este (map), Paraguay (it’s a hectic (but exciting) centre for contraband and cheap electronic goods, but some say it’s not safe there). Each of those three cities having commercial airports.
+ 10 Things to Know Before You Visit Iguazu Falls, Brazil (theculturetrip.com)
+ Iguazu Falls Brazil or Argentina Side? (stingynomads.com)
Border formalities are enforced between the two parks. Crossing the border between these countries is fairly relaxed—authorities assume most people are on a day trip across the border. EU passport holders do not need a visa to enter Brazil for tourism. Also, as of 2019, US passport holders no longer require a visa to visit the Brazilian side of the falls. However, do remember to get off the bus on the border to get your passport stamped. Some bus drivers will not tell you when to do this, so it is best to check with them.
From Puerto Iguazu there are buses from Gate 11 at the main bus station to the entrance of their side of the falls every 20 minutes.
From Foz do Iguaçu buses run every half hour from the bus terminal to the visitor’s centre at the national park entrance, passing many of the main hotels in the city along the way.
It is a good idea to bring some food and water if you are going to spend the day on the park.
Garganta del Diablo (map) – The main attraction of the Argentine side, translating to the “Devil’s Throat”. There is a free train running up to a 1 km-long walkway across the river to stand just back from the main horseshoe of falls where the roar and spray are most tremendous. (from the Brazilian side you get an excellent overview of Garganta del Diablo (from afar) and the rest of the falls.)
There are five main tracks all of which are paved and well marked with the exception of Sendero Macuco.
Sendero Macuco – is the trail through the rainforest to the Arrechea waterfall and is a good way to get away from the crowds. It’s about 7 km return on an unpaved but easy path starting at the Estacion Central. Swimming is possible beneath the fall, so consider bringing a bathing suit and towel. An informative brochure for the trail is available from the park information desk. It is recommended to do it in daylight, so don’t start it if it’s 15:00 or 16:00.
Other than visiting the falls, the activities offered by tour operators on both sides of the park and having a drink or dinner at either Puerto Iguazú or Foz do Iguaçu there isn’t much else to do in this area. 2 or 3 days should do it. For the Brazil side you need no more than 4 hours total. It’s often cheaper to fly out of the Brazilian side to São Paulo for example, than to take the bus (not to mention quicker).