is it legal to drive in puerto rico with a learners permit form another state?

Well, I suggest you to call to any rental company in Puerto Rico such as Hertz, Budget, Avis, etc. The ones located at the Luis Munoz Marin Airport so they can help you. That will be the case if you are going to rent a car.

If you are going to borrow a car from a friend here or a situation like that, that does not involve renting a car, it will depend. I'm not proud of what I'm going to say but, if police man pull you over here in Puerto Rico, he will probably does not speak English and probably will let you go, if is minor violation of driving like crossing a red light or don't having your seat belt on. If he stops you and ask you for your driver license and the license does not show clearly that is learners permit, he will not notice it. Also, if he does not notice it and give you a ticket. The process to register the fines on the driver's licenses in Puerto RIco it's really slow, so, probably yo will never have issues with the ticket expedited to the license because I don't think that the ticketing registry here have any communication or link with the states of the US.

One can't force any wherein with a learner's enable besides a thoroughly license driving force is within the entrance seat with her or him. That is going for any state. So what you're pronouncing and short of to do is not going to fly with out that grownup with you and so much time with a learner's enable there are regulations on wherein and while you'll be able to force besides.