Safe spaces are increasingly utilized to reduce alcohol-related harm, violence, crime and improve public safety in nightlife settings. This study aimed to determine the impact and return on investment of the Take Kare Safe Space (TKSS) program—a harm reduction program implemented to address alcohol-related violence and disorder in three locations in Sydney’s night-time economy between 2014 and 2019. TKSS ambassadors provided support at static safe spaces and patrolled designated nightlife precincts to provide practical assistance to vulnerable and intoxicated people. Ambassadors recorded information relating to these interactions including ‘client’ age, gender, perceived level of intoxication, time and length of engagement with the program. Costs of program implementation and benefits of major incidents averted were obtained to allow calculation of return on investment. From December 2014 to April 2019, 66,455 people were supported by TKSS ambassadors. Most users were male (62%) and aged 18–25 years (66%). Of 3633 interventions by ambassadors, serious risk of harm was averted in 735 cases (20%). The program’s return on investment is estimated at 2.67, suggesting that a $1 investment results in $2.67 in benefits. Safe Spaces are extensively utilized, particularly by young males with high levels of intoxication, and represent a positive return on investment. Despite the growth of such services, there remains a notable absence of rigorous, independent evaluation regarding the outcomes and/or social benefit of safe space programs. From a policy perspective, there is a need for more high-quality economic evaluations to better inform decisions about competing uses of limited resources.