Although conference preparation (CP) has been widely reported to be the foundation for successful interpreting, little is known regarding how interpreters prepare in real-life settings and adapt their preparation strategies to the context. To fill this research gap, the present study analyzed and compared the CP strategies and processes of interpreting novices, intermediates, and experts from the perspective of naturalistic decision making (NDM), a research paradigm for elucidating an expert’s decision-making processes in natural settings with characteristics including time pressure and high stakes. This study adopted observation and interviews as the methods of data collection. Twenty-four participants (ten novices, six intermediates, and eight experts) were asked to prepare for a mock assignment within 30 minutes by using a slide deck. The desktop activity of the participants was recorded by a screen-recording program, HyperCam, for analysis. A semistructured interview was conducted after the participants had prepared. The results indicate that the participants focused on different facets of preparation, which were mainly the language and knowledge facets, when they faced time constraints. Most notably, the experts were better able to assess the characteristics of the context on the basis of their experience, whereas novices focused more on microcontextual details. By connecting NDM with CP, the present study offers an exploratory description of CP in time-pressure situations, yields insights into how experts master preparation, and offers suggestions on how trainees can attain CP expertise.