The mRNA vaccines first rolled out in Japan in mid-February 2021. According to the search results, Japan approved the first mRNA vaccine by Pfizer-BioNtech on February 14, 2021. Vaccinations for the general public started around the same time.

5 Citations

Delayed COVID-19 vaccine roll-out in Japan - PMC

https://pmc.ncbi.nlm.nih.gov/articles/PMC8172150/

Years of research laid the groundwork for speedy COVID-19 shots - Japan Today

https://japantoday.com/category/features/health/years-of-research-laid-the-groundwork-for-speedy-covid-19-shots

Japan virus vaccine roll-out haunted by history - Asia Times

https://asiatimes.com/2021/01/japan-virus-vaccine-roll-out-haunted-by-history/

Japan Leaps Toward Digital Records System as Vaccines Roll Out to the Public | JAPAN Forward

https://japan-forward.com/japan-leaps-toward-digital-records-system-as-vaccines-roll-out-to-the-public/

Japan's vaccine programme chief denies reports of May roll-out | Reuters

https://www.reuters.com/article/us-health-coronavirus-japan/japans-vaccine-programme-chief-denies-reports-of-may-roll-out-idUSKBN29P097/