Can't live in PR for 10 years prior to establishing residency?

I’ve heard you can’t qualify for act 60 if you lived in PR for any of the 10 years before you establish residency. Is that true?

That is incorrect. The stipulation is that you are not a resident of PR during the 10 years prior to Act 60 legislation being signed, i.e. 2009-2019. here’s the full text from Act 60, from page 35, article (4):

an individual … who is a Resident Individual of Puerto Rico, but has not been a Resident Individual of Puerto Rico for the last ten (10) taxable years prior to the effective date of this Code…

Here, effective date meaning when the law was passed in 2019, not when you apply for or receive a decree, nor when you establish residency. My CPA confirmed this

One of the main questions you will see it in the application itself (as you are doing a sworn statement when submitting the application) is “Has the Applicant been a bona fide resident of Puerto Rico at any time within January 17, 2006 and January 17, 2012?

There are some considerations for locals during that timeframe and for that reason those that apply for that tax incentive should state on what state or country they were a resident from. Furthermore, you need to submit a tax filing certificate, that if by any chance you were a resident will come up there as well. Validating process is very strict these days and they make substantial cross-reference between many agencies.