Grennia generally experiences low levels of crime overall, with violent crime being especially rare.
The most common crimes in Grennia include stalking, unarmed theft, vandalism, bank fraud, and internet scamming.

The minimum age for prosecution in juvenile courts is 8, and the minimum age for adult criminal prosecution is 18.

Hotspots for crime include the western portion of Satogeko City and the southeast of Keromatsu City.

The emergency hotline is 999 (police, fire, ambulance) and 1190 is for non-emergency police responses.

Current as of 2025.

Physical crimes reported (2025): 14,558
227 of these cases were reported to be violent.

Most common physical crimes:
Stalking (1,722 cases reported)
Shoplifting and unarmed theft (3,782 cases reported)
Vandalism (4,241 cases reported)
Disorderly conduct (2,486 cases reported)
Other (2,100 cases reported)

Financial crimes and scams reported (2025): 48,187

Most common financial crimes:
Bank fraud (19,842 cases reported)
Internet scamming (11,221 cases reported)
Tax fraud (5,928 cases reported)
Other (11,196 cases reported)