Ptuj is generally safe for solo female travelers. Locals are welcoming and the crime rate is relatively low. However, being the oldest town in Slovenia, it does get busy with tourists, so it's always recommended to remain cautious about pickpocketing or minor thefts, especially in crowded places. Plus, as it's a small city it can feel quite isolated at night, so it's advised to stay in well-lit areas and take organised transport rather than walking alone after dark. Overall, common sense and standard travel precautions should ensure a pleasant visit to this charming Slovenian city.