Foz do Iguazu is the border town on the Brazil side of the International border, while Puerto Iguazu is the border town in Argentina. By car it doesn't take long to get between the two cities, unless the immigration lines are large.
There are 2 ways to get between Foz do Iguacu to Puerto Iguazu. Firstly there is the cheap, but tedious journey by local public bus; and secondly there are the more expensive, but very easy transfers.
By Local Bus
There are local buses from Foz do Iguacu to Puerto Iguazu, operated by several companies. The trip by local bus is not that straight forward and a bit of a hassle if you have to do the Brazilian immigration on the way, but it is possible and the following is how you can do it.
If you are going straight to Puerto Iguazu once you arrive, from the Foz do Iguacu long distance terminal, look for the buses which say TTU which will take you downtown and terminate at the domestic terminal called Terminal Transporte Urbano (TTU). Once there exit the terminal and just outside you can catch the local International bus which is signed: Puerto Iguazu Argentina.
If you are already staying in Foz do Iguacu, and not sure if the bus passes your hotel, the easiest way to take the bus is to also go Terminal Transporte Urbano, but instead of entering the terminal, cross the road and find where the buses to Puerto Iguazu depart.
Once on the bus you need to remind the driver that you need to get off at the Brazilian border to stamp out of Brazil otherwise they might not stop. This is because the locals do not need to do immigration on the Brazil side, so they only stop if you ask. Make sure you keep an eye out for the Brazilian immigration office during the trip, or you may find yourself a couple of Kilometers away at the Argentine side and have to figure out how to get back.
The bus will not wait for you on the Brazilian side, and as you get off you need to ask the driver to give you a ticket to catch the next bus. Important to note that there are several companies who do this route and the ticket they give you is only valid for the same company, so note the name on the bus you just got off. The average waiting time for the next bus of the same company is 40 minutes.
After you finishing the immigration on the Brazil side and are back on a bus, you travel down the road and then over a long brigde that spans the Iguazu river before you are prompted to get off the bus at the Argentine Immigration. This time everyone must get off the bus and file into passport control and immigration where they check your bags. Remember to take everything off the bus with you.
This time the bus will wait a few minutes for you if the queues at immigration are not enormous, so once you have your passport stamped, jump back on the bus and you will then continue another 20 minutes to the Puerto Iguazu bus terminal.
If you are just going over to visit the falls, once you get to the Puerto Iguazu terminal, you need to find the local buses which travel 30 minutes to the National park. Remember that you cannot pay your entrance to the falls with any other currency other than Argentine Pesos, and they do not accept Credit Cards. This means that if you only have Brazilian Reals or other currencies on you, you will need to find a currency exchange or ATM before you take the bus to the falls. Once inside the park, the shops and restaurants do accept other currency and cards, but be aware that everything on the Argentine side is rediculously expensive and its a good idea to buy water and snacks at the bus terminal to save a few bucks.
If going back to Foz do Iguacu, you need to do the whole thing in reverse, including changing buses at the Brazilian Immigration after stamping back in.
These buses cannot be booked in advance online.
By far the easiest way to cross from Foz do Iguacu to Puerto Iguazu in Argentina is by transfer. Not only do you not have to wait for buses on the Brazilian side, you also do not have to get out of the vehicle on the Argentine side because the transfer will drive up to a booth where you hand your passports over to the attending official. At the Brazilian passport control you do however need to exit the vehicle and go inside to get your stamps, and most drivers will escort you in and show you where to do this.
If you are need transport from Foz do Iguacu to the Puerto Iguazu airport, do not bother messing around with local buses unless you have a lot of time. There are no buses to the airport itself, so you will still need to take a taxi once you arrive to the Puerto Iguazu bus terminal.
If you are going to visit the Argentine Side of the falls, transfers allow you more time to explore the park, otherwise you need to count on a few hours to get there and to come back. To see the Argentine side of the falls properley you need about 6 or 7 hours inside the park. Withen you go by transfers, you set a time for your driver to come back and pick you up at the entrance for the return trip.
You can book cross-border transfers from Foz do Iguacu to Puerto Iguazu airport, city and also Agentine Side of falls day trips here: Iguazu Transfers
Buses from Foz do Iguacu to Puerto Iguazu
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