The Argentina eSIM works across Puerto Iguazú town and within Iguazú National Park on the Argentine side, with Movistar coverage at the main viewpoints, the Devil's Throat (Garganta del Diablo) walkway, and around the visitor center. Crossing the border to the Brazilian side or to Foz do Iguaçu means leaving the eSIM's coverage area — it's an Argentina-only plan, so data stops at the border. If you plan to do both sides on the same day, save offline maps for the Brazilian route or buy a separate Brazil eSIM.