How can we find out when were the binary logs of a MySQL RDS instance created?

Hi, yeah currently I think there is no way to achieve the feature you mentioned due to the reason RDS is managed. Did a research as well, similar topic discussed from the community: https://dba.stackexchange.com/questions/223848/show-created-date-of-all-binary-logs --> For on-prem MySQL you will have filesystem access for last written time.

If you want this feature to be developed, I would suggest you raise a feature request through the RDS console:

Navigate to the left lower corner of the RDS console page --> Click Feedback --> For the drop down choose "Feature request".