BACKGROUND: Individuals who have been diagnosed with melanoma have more than a 9-fold increased risk of developing another melanoma. Ultraviolet radiation (UVR) exposure following a melanoma diagnosis can be modified to reduce risk of a new melanoma diagnosis. Yet research shows that many melanoma survivors do not report optimal sun protection practices. The objective of this study is to evaluate the effectiveness of a UVR-sensor wearable device to improve sun protection behaviors and reduce sunburns in a randomized controlled trial (RCT) in melanoma survivors. METHODS: We will conduct an RCT among 368 melanoma survivors in two waves (Summer 2020, Summer 2021). This approach allows for adequate recruitment of the required sample and potential improvements to recruitment, compliance, and retention strategies between waves. The intervention includes an informational brochure about sun protection behaviors and a commercially available UVR-sensor wearable device (Shade), which accurately measures UVR. The device, along with its associated mobile application, measures and stores UVR exposure. As UVR exposure accumulates, the device provides notifications to increase sun protection action. Survivors in the control group receive the device and a separate mobile application that does not provide notifications or summary UVR exposure data. Participants will be asked to wear the device for 12 weeks. They will complete surveys about their sun behaviors at study entry, every 4 weeks during the intervention, and 1 year later. At the end of the intervention period, intervention and control groups will be compared for differences in a summary measure of sun protection habits and experience of a sunburn. We will also measure self-reported physical activity, depression, and anxiety to examine potential unintended negative consequences of the intervention. DISCUSSION: The study intervention will be completed Fall 2021, with anticipated results available in 2022. If this intervention improves sun protection behaviors in melanoma survivors, these findings would support expanding the use of this technology with other populations at high risk for melanoma. TRIAL REGISTRATION: ClinicalTrials.gov NCT03927742 . Registered on April 15, 2019.