One way to promote autonomy in the second language can be through the use of Self-access Centres (SACs). These are spaces for students to engage in activities such as self-study or communication with other learners, or native-speakers of the target language. However, merely having these spaces available does not guarantee that students will use the facility effectively, or even attend at all, so a degree of learner motivation linked with visiting the SAC would be necessary. Deci and Ryan's (1985) Self-Determination Theory (SDT) has been used as the base for numerous studies in second language learning, including those in Japan. Proponents claim SDT is both universal and can be measured on different levels, which are global, situational and state. The authors sought to validate a measure of four subscales of SDT (Intrinsic Motivation, Identified Regulation, Introjected Regulation and External Regulation) written for this study at the situational level among undergraduates using an SAC at a Japanese University (n = 83). The rationale for items at this level comes from the field of psychology (Vallerand & Ratelle, 2002) and a study of second language constructs (Robson, 2016). A factor analysis confirmed four reliable factors, as hypothesized. Further, simplex correlations between the subconstructs somewhat confirms the underlying continuum posited by SDT researchers. These results may lead to a body of work that validates SDT theory in second language learning.