In Armamar, a rural municipality in Portugal’s northern interior, a primary-school microbiology programme has been designed to reach every child and return each year. We report its first two cycles, combining universal participation with increasing conceptual complexity. In 2025, all 153 pupils of Armamar’s public primary school (aged 6–10) took part in “The Invisible Life of Bacteria” educational workshop during school time, exploring bacterial diversity, structure, habitats, and functions. To our knowledge, this was Portugal’s first hands-on microbiology initiative, scientist-led, reaching every pupil across four primary grades in a portuguese public school. In 2026, the programme reached all 153 pupils. New first-year pupils entered the foundation workshop, while returning cohorts progressed to “Microbe Hospital: Mission Antibiotics”, using models to distinguish bacteria from viruses, explore antibiotic action and investigate how antibiotic exposure selects for resistant bacteria. Continuity was secured through a partnership among the school cluster, municipality, NGO and university. Post-workshop questionnaires (2025/2026) captured perceived learning, motivation and experience ratings. 86.0%/85.8% of students reported learning new things, 74.3%/74.0% were motivated to learn more about microbiology and 96.5%/98.4% evaluated the experience very positively. These cycles provide preliminary evidence that year-on-year microbiology educational activities in primary schools are feasible while sustaining high engagement in rural public schools. Armamar’s transferable contribution is not a workshop, but what made return possible: universal school-time access, hands-on enquiry, conceptual progression and sustained partnerships. If responsible antibiotic use is a public-health expectation, access to the microbiology that makes it meaningful cannot depend on geography or chance.