BACKGROUND: Suicide is a leading cause of death in US adolescents and adults. Caring Contacts - non-demanding messages of care and support - can significantly reduce suicide risk, but important implementation questions remain. Two-way Caring Contacts texts (CC2) (to which recipients can reply) have evidence of efficacy, but in practice health systems typically send one-way Caring Contacts texts (CC1) (to which recipients cannot reply). This manuscript describes the protocol for the Comparing Suicide Prevention Interventions to Guide Follow-up Care (SPRING) Trial. METHODS: The SPRING Trial is a pragmatic randomized controlled trial designed to compare the effectiveness of CC2 and CC1 versus UC, and to determine whether CC1 are noninferior to CC2 for preventing suicidal behavior. The sample includes 849 participants 12 years or older who screen positive for suicide risk and receive usual care at a primary care or behavioral health clinic. Participants are randomized 1:1:1 to CC2, CC1, or UC, with participants unaware of the alternative treatments. The state 988 crisis and suicide hotline delivers both active interventions and the feasibility of this model will be described. The primary outcome is suicidal behavior, measured using the Harkavy-Asnis Suicide Scale (HASS). Secondary outcomes include suicide attempts, suicidal ideation, ED utilization, hospitalization, and outpatient mental health treatment. Outcomes are assessed via surveys at baseline, 3, 6, and 12 months. DISCUSSION: CC2 is more operationally complex than CC1. If CC1 is non-inferior to CC2, it could more feasibly be implemented at scale, increasing access to effective suicide prevention care. Clinical trial registration The SPRING Trial is registered at ClinicalTrials.gov (NCT06128239).