Exploring Being Autistic is an autistic-led group-based programme providing psychoeducation and peer support to newly identified/diagnosed autistic adults. In 2020, due to social distancing measures implemented following the coronavirus pandemic, Exploring Being Autistic was adapted for online delivery. Here, we aimed to replicate previous research into the in-person delivery of Exploring Being Autistic, to determine whether similar results were obtained when the programme was delivered online. Further, we aimed to identify the unique opportunities and challenges that online delivery afforded. We used a community-based participatory research (CBPR) approach, whereby the autistic developer and facilitator of Exploring Being Autistic worked collaboratively with a team of academic researchers throughout the research process. Together, we evaluated two iterations of the online Exploring Being Autistic programme, involving 16 attendees. Attendees completed questionnaires before, during and after the programme. Attendees were also invited to participate in two post-programme (group or individual) interviews: one following the completion of the programme (time one) and another 6-8 months later (time two). Attendees were included in the research if they completed at least one questionnaire or interview. Data were analysed qualitatively, using reflexive thematic analysis. Experiences of participating in the programme tended to be positive. Participants appreciated the autistic-led nature of the programme, found unity in the diversity of the group, and developed a positive and practical outlook as a result of the programme. Further analyses of our data revealed mixed views regarding the online delivery of the programme. Opportunities of online delivery were noted, such as this mode of participation reducing cognitive load, enabling the programme to be accessible to more participants, and fostering meaningful social connections among participants. However, technology and practical issues were felt to cause barriers, and some human aspects of participation were felt to be 'lost in translation' (e.g., in breakout groups). The online delivery of the Exploring Being Autistic programme yielded similar results to previous, in-person evaluations of the programme. While we identified positive aspects of online delivery, this mode did not entirely suit everyone's needs. From the current findings, we can make several recommendations to develop online support for autistic people. First, flexibility is key. To make support accessible and inclusive to a broad range of autistic people, the option for attendees to engage in-person, online or in hybrid formats should be considered. Second, if delivering support online, the use of breakout rooms should be carefully considered. While participants appreciated the opportunity to meet different people, some participants found the unpredictability and lack of scaffolding associated with breakout rooms challenging. To mitigate these challenges, groups could be pre-determined and shared with the attendees in advance (although consideration should be given to how the groups 'fit' together, and whether groupings should be changed at set intervals). Gentle warnings should also be given to those in breakout rooms, to alert them of the need to re-join the main group. Finally, support with technological aspects relating to engagement should be prioritised.