It is not mandatory to visit Iguazú Falls, and not required to enter Argentina as a tourist. It is, however, commonly recommended for travel to the subtropical northeast, and some travelers choose to have it.
Why to ask early
The yellow fever vaccine takes roughly ten days to become fully effective. If you decide you want it, that decision belongs weeks before you fly, not in the days before departure. That timing is the main reason to raise it now instead of filing it under things to sort out later.
It can also matter for what comes after Argentina. Some countries ask arriving travelers for proof of yellow fever vaccination when they have come from areas where it circulates, so an onward itinerary can quietly turn a recommendation into a requirement. That depends entirely on where you go next.
Who to ask
Your own doctor or a travel clinic, not a forum, not a tour operator, and not us. Guidance genuinely varies by nationality, by medical history and by the shape of your trip, and the vaccine is not suitable for everyone. It is worth getting a clear, current answer before you travel rather than during.
What we can tell you about the park itself: the real day-to-day nuisance is mosquitoes, not exotic disease. The walkways run through subtropical rainforest, so bring repellent and reapply it during the day. That is the part you will actually notice.
