The Community of Inquiry (CoI) (Garrison, Anderson & Archer, 1999; 2010) is well-established, widely accepted, and practical framework. It highlights social, cognitive and teaching presences in effective online learning communities. 23 Things International (23T) is an online, flexible course for research students and early career researchers. The course is self-directed and promotes the building of academic and research networks, familiarity with resources underpinning research, and establishing professional profiles. It was first implemented in 2020 and has been refined annually to better meet needs of participants. One of the features of the programme is the ‘pod group’ arrangement. Participants are connected to each other in groups (the pods) based on research interests. The size of the pods is kept to about ten, so to facilitate manageable and meaningful communication and discussion of topics within the programme. Each year, 23T participants have reported pleasing satisfaction levels. Using the CoI, this investigation examined possible reasons why. The study aimed to: (a) identify practices and structural mechanisms that seem to underpin the experienced success of 23T; and (b) articulate plans for more targeted evaluation-review-development. Data sources included: annual reports (2020-2023) on the course containing integrated analyses of participant evaluation data; the outline and structure of 23T, showing the fabric of the course, how it is organised and arranged and how it implemented; facilitators’ knowledge and experiences of conducting 23T. Data were organised using a simple matching process (Garrison et al, 1999). CoI elements were matched with practice examples from implementation, and evidence from the data. Positives, negatives, possibilities and conclusions were drawn about gaps and potential. Examples of evidence drawn the from the data sources about the 23T programme include: Teaching Presence: including the use of prompts built into the material presented online and the facilitators’ spoken and written interactions with participants through live activities and through blogs (boosting authentic participant application of their learning); Social Presence: pod groups and how they were arranged and supported; Cognitive Presence: range of topics covered and the participant activity surrounding the topics. To build on theoretical work investigating 23T (Stein, Sim & Rose, 2023), this study is helping us to pinpoint concrete elements that seem to be influencing online course effectiveness and enabling identification of ways to strengthen 23T’s future flexibility and attractiveness. This is pertinent because of the uniqueness of 23T, namely, that it is online, flexible and self-guided and has no formal assessment expectations and does not provide formal credit. Gauging what counts as effectiveness and success is quite different therefore from award courses normally offered by higher education institutions. Similar application of the CoI using our matching approach may be helpful for others in different contexts and settings who are planning and/or implementing online courses.