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Earthquakes preceding large events are commonly referred to as foreshocks. They are often considered as precursory phenomena reflecting the nucleation process of the main rupture. Such foreshock sequences may also be explained by cascades of triggered events. Recent advances in earthquake detection motivates a reevaluation of seismicity variations prior to mainshocks. Based on a highly complete earthquake catalog, previous studies suggested that mainshocks in Southern California are often preceded by anomalously elevated seismicity. In this study, we test the same catalog against the Epidemic Type Aftershock Sequence model that accounts for temporal clustering due to earthquake interactions. We find that 10/53 mainshocks are preceded by a significantly elevated seismic activity compared with our model. This shows that anomalous foreshock activity is relatively uncommon when tested against a model of earthquake interactions. Accounting for the recurrence of anomalies over time, only 3/10 mainshocks present a mainshock‐specific anomaly with a high predictive power. Plain Language Summary: Recent observations in Southern California have suggested that the majority of large earthquakes are preceded by an elevated seismic activity. The anomalous character of those foreshock sequences is debated since episodes of elevated seismic activity are generally not followed by a mainshock. Here, we compare these observations to a seismicity model that accounts for the natural clustering of seismicity due to earthquake interactions. Even using a highly complete earthquake catalog, we find that the majority of mainshocks present a seismic activity similar to what is expected by our model. We note that only 10 out of 53 selected mainshocks are preceded by episodes of anomalously high seismic activity. Whether these episodes cause the mainshock, or are simply coincident with it, is generally unclear: only for 3 out of these 10 instances, the coincidence appears very unlikely. Key Points: We further investigate previous claims of significantly elevated seismic activity prior to large earthquakes in Southern California10 out of 53 mainshocks are preceded by anomalously high seismicity, but only 3 of these anomalies are exclusively related to the mainshockThese selected foreshock sequences are likely due to additional pre‐slip, aseismic processes [ABSTRACT FROM AUTHOR]