Abstract Understanding the cause of spatial variations in seismicity is crucial for comprehending the physics governing earthquake activity. Off Iwate, in the northern Japan Trench subduction zone, the plate boundary can be divided into three distinct zones based on depth‐dependent slip regimes: the slow earthquake, asperity, and stable creeping zones. We statistically compare their seismicity characteristics. Our results demonstrate that the slow earthquake zone produces significantly more aftershocks, whereas the asperity zone exhibits the lowest seismic activity. Conversely, the stable creeping zone has the highest rate of background seismicity. We interpret these distinct characteristics based on the respective broad‐scale slip behaviors. Moreover, we identify a clear kink in the cumulative magnitude‐frequency distribution within the stable creeping zone. Calculations of rupture arrest probability suggest a characteristic rupture size of M 3.7 (∼1 km scale) in this zone. The proposed rupture arrest probability may prove useful for future studies on earthquake source physics.