I'll include here my reply to a question posed to me recently about this very same subject. It is based on bonafide legal research I made at the University of Puerto Rico Law School:
The law and judicial interpretation can be summarized as follows:
You can forget carrying fixed blade knives around, UNLESS you are carrying it for purposes of an art, sport, profession, occupation or trade. Several other weapons or tools fall under this statute. As you can guess, it is difficult to trigger the exception clause above and you are better off not carrying any fixed blades around. I myself like to carry a fixed blade on occasions...an Emerson La Griffe neck knife with a 1.75 blade, tucked under a shirt. I dont know whether carrying this is illegal, but it is so unobtrusive that I dont tend to worry much.
What you MAY carry, is a FOLDING knife whose blade measures LESS THAN 3 inches from the tang to the tip of the blade. That is, from where the handle ends and the non-sharpened part of the knife begins, all the way up to the tip (in other words I am not referring to merely the sharpened part of the blade). You have to measure the ENTIRE blade to determine its length in this jurisdiction.
I sometimes carry a Spyderco Native clipped to my pocket or hidden inside it. Also a Spyderco Starmate. These are both ILLEGAL (Native is 3 1/8 long, Starmate is 3.75 long) to carry with you out in the open. Dont ask me why I do it, I just do so. I just want to make sure that when the sh#$ hits the fan and I have no way of getting out of a deadly situation, I am properly armed to defend myself. The situation is aggravated if you brandish them in any way around other people.
However, my Spyderco Calypso Jr. (2 7/8) and my Spyderco Dragonfly (2 1/8) would not fall under the illegal sort, since their blades, as I understand, measure less than 3.
If I were you, I would first worry about passing a knife through customs (the airport) well hidden in some carry-on bag or, better yet, hidden in your suitcase. Once you get here, you dont have to pass again through a metal detector (until you leave back for the U.S.). If you can do this successfully, you can carry your FOLDING knife around Puerto Rico without worry clipped to your pocket or in other concealable methods. Just make sure that the blade is NOT 3 long or more. And try not to open it in front of crowds of people or law enforcement officials, since that could be deemed at least suspicious behavior.
By the way, keep in mind that this is what the LAW says. As happens everywhere, policemen are not carrying books of law around and might hassle you if they catch you using a knife inappropriately. Still, this doesnt mean that they will stop you if youre carrying it clipped to your shorts or pants. So far, I have never been stopped, but have been prudent by not brandishing it in places where there are many people around.
As for self-defense, if your life is unequivocally in danger, you can meet the enemy with force to save your life. However, first keep in mind that you cant use excessive force when met with little force (e.g. a man is going to punch you and you draw a SIFU and slash his throat). Also, that wont stop the prosecutor from charging you for possessing and carrying an illegal weapon.
As for interesting places to visit, there are several. I suggest going to the Tourism Department's office as soon as you arrive at the airport. They have many brochures, a magazine titled "Qué pasa?" which is essential, maps, and there are people around to answer your questions. For that matter, you can visit:
1) The "El Yunque" rainforest over to the east/northeast area
2) The "El Morro" fortress in Old San Juan (plus the surrounding area)
3) The Camuy caves close to the west/north-western part
4) Take a drive through the "Panoramic route" which goes around the mountainous region in the center of the island
5) The "Isla Verde" area, especially the San Juan hotel (not sure it's named like that anymore) with its excellent casino
6) Try getting to Luquillo beach over to the east, very clear water, beautiful beach with facilities.
And these are just a few places! Any other questions, feel free to email me!
-Flood
