Introduction: Safety planning type interventions (SPTI's) are brief suicide-specific interventions. Little is known about safety plan use during high-risk periods, and whether safety plan use is influenced by baseline characteristics. This study examined how adolescents recently hospitalized for suicide risk use their safety plans post-discharge, tested moderators of safety plan utilization, and explored the relationship between changes in utilization and changes in suicidal ideation (SI) over time. Methods: Seventy-eight adolescents hospitalized for suicide risk who participated in a pilot trial of safety planning responded to one survey/day for 4 weeks post-discharge and completed a 1-month assessment. Results: Over 90% of adolescents reported having access to their safety plan during the month post-discharge. Safety plan use and SI declined over time. No baseline characteristics predicted safety plan use in the 4 weeks after discharge, or changes in safety plan use over time. However, the relationship between changes in safety plan use and changes in SI was moderated. For girls, SI and safety plan use rose and fell together; for boys, safety plan use declined regardless of changes in SI. Conclusions: High-risk adolescents retain and use their safety plans. Results underscore the importance of looking at sex effects on SPTI utilization.