Enable Object Lock on Existing Bucket

I have just looked up support center and there is no option to raise tickets related to S3 object lock though documentation asks to contact support. There is no support for services under basic support plan. However I would still suggest you try opening a case by selecting Service Limit Increase and Simple Storage Service. If you are able to open a ticket it may not reach the right team but you are likely to get support on further action or the right procedure. If you are unable to open a ticket then select Account and Billing support and then select General Info and Getting started and then select Using AWS and Services to open a new case. Opening some support case should help you get the right directions. Nothing wrong in opening cases as you have a few options to choose from in Basic support plan. Atleast you will get to know if you can enable object lock for existing buckets via support staff. Hope this helps. Please keep us posted of your progress so we can learn as well.

@Draenoel did you have any success with the approach Sandeep suggested? I'm facing a similar issue (enabling replication on an object lock bucket), currently.