Porto Seguro in Brazil is generally considered safe for solo female travelers. Like with any city, it's recommended to take standard precautions for personal safety. There's a good level of police presence in tourist areas, but it's best to avoid isolated areas especially after dark, and always keep an eye on your belongings particularly in crowded places. Crime rates are relatively low, especially against tourists, but it never hurts to be aware of your surroundings and trust your instincts.