Luquillo is generally safe for solo female travelers. Like any destination, it's essential to remain vigilant, especially during the night or when visiting less crowded areas. The locals are friendly and willing to help. Serious crimes are relatively rare, but petty theft like pickpocketing occurs occasionally. As long as you take regular travel precautions, such as not displaying expensive belongings and always being aware of your surroundings, you should have an enjoyable and safe visit.