The experience of transferring to a 4-year college, especially in STEM programs, can be particularly challenging for students. While much of the onus for preparing students for transfer has been placed on community colleges, the 4-year institutions to which students transfer have critical roles to play. With this in mind, we established the Pre-transfer Interventions, Mentoring, and Experience in Research (PRIMER) program to support students transferring into the biology department at our university. The design of this program is based around the key elements of Schlossberg's Transition Theory, focusing on the support and strategies elements of the theory. Through a weekly academic skill course, peer mentoring, and informal academic and social supports, our goals were for students to increase their involvement in the campus community and to increase their use of academic support resources. We used qualitative and quantitative assessments to compare sense of community and use of campus resources between students who participated in our program and others. We found that students in our program strongly increased their sense of community during the semester compared to other students and used campus resources at a higher rate. Our insights from the PRIMER program can help others in developing programs to support transfer students in biology departments.