Participation in professional learning communities (PLCs) has enhanced teacher planning and curriculum implementation during the regular school day, but PLCs have not been studied in connection with after-school programs. This comparative case study investigated the interactions of Teacher-Coaches during after-school PLCs at two rural middle schools in the southeastern U.S. as they planned for STEM Clubs, asking: 1) How did the Pre-Club meetings develop the T-Coaches' community of practice (CoP) and what were their perceptions of their usefulness? and 2) What did STEM Club observations and T-Coaches indicate about the success of the clubs? The CoP social learning framework was used to assess PLC quality based on audio transcripts of Pre-Club PLC meetings and individual interview data. The Dimensions of Success (DoS) observation tool and interview data were used to understand club success. Pre-Club meetings were found to be essential for the development of the CoP (repertoire, mutuality, and enterprise). Absences at Teacher Professional Development changed the nature of the CoP and undermined STEM Club success, based on DoS ratings. Pre-Club meetings were vital to allow T-Coaches the time to plan for the clubs, develop relationships, and increase STEM club success. Conclusions and future research directions will be shared.