The S3 license is available on the NetApp Support Site at the following page. If you have an account, you can download it here.
・Master License Keys
https://mysupport.netapp.com/site/systems/master-license-keys
It also worked without issues in my simulator environment as shown below.
cluster1::> version -v
NetApp Release 9.12.1P18: Wed May 07 12:18:07 UTC 2025 <1O>
cluster1::> license add -license-code XXXXXXXXXXXXXXXXXXXXXXXX
(system license add)
License for package "S3" installed.
cluster1::> license show
(system license show)
Serial Number: 1-80-000011
Owner: cluster1
Installed License: Legacy Key
Capacity: -
Package Type Description Expiration
----------------- -------- --------------------- -------------------
S3 site S3 License -
