Objective <p>Although research continues to explore the broad applications of mindfulness meditation, the precise mechanisms underlying its health benefits remain unclear. Paced breathing, which involves intentionally slowing the breath, shows similar benefits. The shared focus on breath in both practices may partly explain their positive health effects. This study explored the impact of mindfulness meditation and paced breathing on electroencephalography (EEG) and skin conductance level (SCL), to investigate changes in brain function and sympathetic arousal.</p> Method <p>Eighty healthy young adults were randomly allocated to either a <i>mindfulness meditation</i> (<i>n</i> = 40; <i>M</i>_age = 20.15; 32 females) or <i>paced breathing</i> (<i>n</i> = 40; <i>M</i>_age = 20.15; 32 females) task. EEG and SCL data were recorded during the allocated task and two 5&#xa0;min eyes-closed resting states, immediately before and after the task. The effects of condition (mindfulness meditation vs. paced breathing) and state (pre-task vs. task; pre-task vs. post-task) were investigated.</p> Results <p>Significant interactions between condition and state (pre-task vs. task) demonstrated increased global EEG amplitudes across all frequency bands, as well as increased SCL, during paced breathing. In contrast, mindfulness meditation resulted in a decrease in global alpha amplitude, while the remaining frequency bands and SCL remained somewhat consistent when comparing pre-task with task. No association was found between global alpha amplitude and SCL.</p> Conclusions <p>These findings highlight the differing effects of mindfulness meditation and paced breathing on neural oscillations and arousal, suggesting that each practice involves unique underlying mechanisms that contribute to their respective health benefits.</p> Preregistration <p>This study was not preregistered.</p>