Foz do Iguacu is relatively safe for solo female travelers. As it's a popular tourist destination, the area around the falls and the city itself are both well policed. However, like any travel destination, it’s advisable to take standard safety precautions. Be aware of your surroundings, especially at night, avoid deserted areas, and keep valuable belongings secure. While most locals are friendly and helpful, be aware of potential scams aimed at tourists.