Background: To meet growing demand for training in core bioinformatics skills, we designed and delivered a free, two-part Massive Open Online Course (MOOC)-style course series: Bioinformatics for Biologists (B4B1 and B4B2). These courses provide free, introductory- and advanced-level learning pathways, catering to students and professionals working in genomics research or bioinformatics, and learners aspiring to data science career. Methodology: The first iteration of each course underwent formative evaluation using a mixed methods approach to identify recurring barriers to learning, informing the subsequent runs’ improvements. Results: The main challenges identified included: time constraints, technical difficulties, familiarity with the subject matter, the level of course content, and accessibility issues, all of which could have affected overall engagement with the material. To address these challenges, several improvements were implemented. Technical challenges were mitigated through active facilitation, peer learning support and alternative setup methods, whereas course content was enhanced with downloadable resources, formative quizzes, glossaries and refresher materials, to accommodate varying levels of prior knowledge. Accessibility was improved through transcripts, fall back resources and platform features, ensuring a more inclusive learning experience. The courses were offered at different times of the year and eventually transitioned to a free on-demand format, allowing greater flexibility for learners balancing professional and personal commitments. Conclusion: These enhancements focused on providing an adaptable and supportive environment for core bioinformatics training and resulted in smoother subsequent runs, reaching a global audience, of around 45,000 learners from more than 180 countries, illustrating the potential of MOOCs to bridge bioinformatics skills gaps.