Increasing consumer empowerment and agency in treatment decision-making is a priority for improving recovery among people with serious mental illness (SMI), as it is associated with a number of positive outcomes, including improved treatment engagement and satisfaction. Although there are many tools to promote initiation of shared decision-making by providers, there are few tools empowering consumers to independently initiate collaborative decision-making (CDM). Therefore, this study tests the feasibility of a novel skills training intervention for outpatients with SMI, collaborative decision skills training (CDST). Twenty-one consumers with SMI currently receiving community-based day services participated in CDST. Four areas of feasibility were assessed—acceptability, demand, practicality, and preliminary evidence of efficacy. Feasibility results were favorable, including high acceptability and practicality. Demand results were mixed: rates of attendance were high and attrition was low, but participants did not complete homework as often as expected. Finally, there was evidence CDST has a positive impact on targeted outcomes; participants reported an increased sense of personal recovery, and displayed improvements in both knowledge and skills targeted by CDST. CDST is feasible to implement with fidelity and is received well by participants. Next steps include larger controlled trials of CDST, which will better inform efficacy and implementation related questions.