Mental health has become increasingly important for the applied sport psychologist, a factor which may include screening, promoting literacy, individual support, and educational programmes. Despite this importance, however, few checks have been made on the perceived preparedness of sport psychologists to undertake this work and whether differences may exist between those recently qualified compared to experienced practitioners. Underpinned by the theoretical domains framework, 62 Health and Care Professions Council registered practitioner sport and exercise psychologists (30 females, age: M = 46.13 years, SD = 10.44 years and 32 males, age: M = 43.25 years, SD = 10.47 years) completed an online survey to assess whether they felt equipped to address the mental health dimension of their work. The survey comprised three sections: Demographic and background information, a series of statements (n = 31) adapted from the determinants of implementation behaviour questionnaire, and three questions with space for free text comments, inviting participants to explain their level of preparedness to incorporate and deliver mental health interventions. A 6 x 12 analyses of variance yielded significant differences between domain ratings but not across levels of experience or interactions. Data from free text comments were analyzed thematically and categorized into three themes: (a) Complementing the performance role, (b) Awareness of professional boundaries, and (c) Importance of further CPD. Combined, although practitioners emphasized importance, preparedness ratings ranged from neutral to somewhat agree, calling for further specific sport psychology-based mental health training.