The purpose of the present study was to conduct a process evaluation of intervention delivery for a randomized controlled trial (RCT) conducted during the COVID-19 pandemic (NCT03915548). The RCT tested the effects of a telephone-delivered behavioral intervention on changes in breast cancer survivors' satisfaction with social roles and activities, as compared to an attention control condition. This process evaluation examined (a) fidelity monitoring scores; (b) participants' perceived benefit ratings for gaining confidence, reducing distress, adjusting habits and routines, setting goals, and increasing exercise; and (c) field notes, email communications, and transcripts of coach supervision and debriefing sessions. The behavioral and attention control conditions were delivered with a high degree of fidelity (global quality rating score for the BA/PS condition was M = 4.6 (SD = 0.6) and M = 4.9 (SD = 0.3) for the attention control condition, where "5" is the highest rating). The behavioral intervention participants perceived greater benefits than the control participants pertaining to goal setting, t(248) = 5.73, p = <0.0001, adjusting habits and routines, t(248) = 2.94, p = 0.0036, and increasing exercise, t(248) = 4.66, p = <0.0001. Moreover, coaches' perceptions regarding the behavioral intervention's therapeutic aspects aligned with the study's a priori conceptual model including the use of a structured process to set small, observable goals and facilitate the independent use of problem-solving skills. However, coaches also noted that aspects of the attention control condition, including the perceived relevance of the educational content and opportunities for social support, may have made it more therapeutically potent than intended. The pandemic may have affected the activity goals behavioral intervention participants could set as well as augmented the relevancy of social support provided in both conditions.