Single-event volunteering, one form of episodic volunteering, is increasingly common. To gain a deeper understanding of this phenomenon, this study used self-determination theory to explore the motivations and communication experiences of volunteers for a 1-day volunteer event. Data were collected from 294 volunteers on a questionnaire containing open-ended questions (qualitative) and scaled items (quantitative). Results from the analysis indicated increased feelings of autonomy, competence, relatedness, and purpose, along with reduced feelings of pressure to participate, were associated with increased motivation to volunteer during the recruitment process. Higher levels of motivation, along with positive communication with leaders and peers, resulted in higher levels of satisfaction and likelihood of volunteering again. These results provide evidence for expanding SDT to develop a model of volunteering that includes additional motivations and communication, and provide practical advice for leaders of volunteers.