This descriptive study aims to investigate the satisfaction levels of English as a Foreign Language (EFL) instructors in their professional development activities at a language center situated in the Mekong Delta region of Vietnam. A total of 30 EFL teachers were solicited to provide data through a questionnaire, and six out of the 30 were further selected for participation in semi-structured interviews. This study incorporated two primary techniques for data analysis: descriptive statistics for the quantitative data and thematic analysis for the qualitative data. The study concludes that the EFL teachers exhibited a high level of satisfaction towards the existing professional development activities that involved mentorship, observation, feedback from experts, and learning from colleagues. These activities fostered a supportive, collaborative, and personalized approach to professional development, resulting in the enhancement of the teachers’ knowledge, skills, motivation, and job satisfaction. The results, accordingly, suggest that language centers should adopt a personalized, supportive, and collaborative approach to professional development while also addressing the various factors that hinder teachers’ interest in research and writing.