Many social media affordances can affect the quality of online discourse, but such an effect remains understudied for the visibility of geolocation, which is available on most social media platforms. We looked at the event in which Weibo started to display users’ IP locations on 28 April 2022, which was supposed to reduce incivility as the deindividuation hypothesis predicted. Leveraging a natural experiment, we examined the effect of IP location visibility, with special attention to COVID-19-related news posts and location-based, uncivil name-calling. We found that displaying the IP location in the comments section increased location-based incivility, as geolocation can function as an effective cue that signals ideological affiliation and fuels conflicts between users holding different political positions on the Chinese Internet. Meanwhile, we characterized a moderating effect of audience size on this decivilizing effect. Our study suggests that diverse social media affordances can fuel group identification and facilitate intergroup behaviors.