Background: The delivery of team-based survivorship care after primary cancer treatment remains challenging, in part due to a lack of effective interventions. We developed a multi-level intervention for breast cancer patients and their primary care and medical oncology providers to improve the delivery of team-based survivorship care called ConnectedCancerCare (CCC). CCC includes a patient-facing, personalized mobile website, and tailored feedback letters to providers. Methods: We conducted a pilot randomized controlled trial in a breast oncology clinic to establish the feasibility and acceptability of CCC. Women within one year of completing primary treatment for stages 0-II breast cancer were randomized to CCC (intervention) or a static online survivorship care plan (control). Participants completed online surveys at baseline and 3 months, ascertaining their knowledge about PCP roles in their survivorship care, their communication with their PCP about team-based care, and whether they scheduled a follow-up visit with their PCP. Multiple measures of acceptability were collected among women in the intervention arm (n = 28). Qualitative interviews were conducted at the completion of the study with 5 PCPs, 6 oncology providers, and 10 intervention patients to identify barriers and facilitators to implementing CCC. Results: Among 160 eligible women invited to participate, 66 women completed the baseline survey and were randomized (41% participation rate), and 54 completed the 3-month follow-up survey (83% response rate). Women in the intervention arm found the content of the CCC website to be highly acceptable, with 82% reporting it was easy to use, and 86% reporting they would recommend it to other patients. A greater proportion of women randomized to CCC (vs. control) reported scheduling a PCP follow-up visit (64% vs. 42%) and communicating with their PCP about provider roles (67% vs. 18%). Women in the CCC arm also reported higher mean knowledge scores regarding team-based cancer care (3.7 vs. 3.4). Providers noted challenges to implementing CCC, including integration into electronic medical records, and supporting sustained engagement with CCC over time. Conclusions: Our findings suggest deploying CCC in medical oncology practices is feasible, and the intervention content is acceptable among breast cancer patients. CCC shows promise for improving understanding and communication about provider roles in survivorship care, and facilitating patients to follow up with their PCP early in the survivorship period. Clinical trial information: NCT03618017.