Passau is really safe, you should only be careful during the night around the train station and the central bus station (ZOB). Everywhere else you can walk alone without any safety issues and during the day everything is perfectly safe

It's pretty safe, but I'd generally avoid walking alone around the Inn river at night or around the train/bus station. In my 5 years I've never had an incident where I felt unsafe though. If you're with another friend you'll likely be fine.

As a local woman walking around I feel safe, even at the local bus central and train station. Some areas have low light but regardless I feel safe. As long as you keep up typical precautions I’ve had no problems. Occasionally in broad daylight you have men yelling out of cars at you and maybe a weird guy trying to flirt here and there but I didn’t feel in danger from these encounters. As a woman travelling alone Passau would be 100% safe