In Mexico, the law is in the eyes of the beholder. Scanners may or may not be technically legal or illegal, but Mexico remains a lawless nation, especially in the dangerous border region and in several southern states such as Guerrero, Veracruz and Michoacan. The legality of anything can be determined on the spot by the police or military official questioning you. In the real world, Mexico is still not a completely civilized nation( especially in rural areas and out on the highway far from a modern city), with checks and balances on the police( most of which still have direct ties to organized crime). I have lived off and on in Mexico for the past 30 years and have never seen scanners for sale or have seen anyone with one. However, with a great deal of precaution, I have brought communications receivers and scanners to Mexico over the years, including just 2 months ago. But I fully realize that if I get caught with one, one of several things could happen...either nothing, or confiscation, a pay off and/or imprisonment. I do know that it is illegal to have a receiver receiving police or military transmissions( my god son is a Mexican naval commander). Most law enforcement officers in Mexico have no idea what a scanner is, as they are not legally sold in Mexico. If they see a scanner or similar type of communications receiver, they more than likely will think that it is a business handheld radio, which are completely legal. If you think that it is legal to have a radio receiving police communications in Mexico, just tune in to a police frequency and walk by some police officers with the radio on and active, and see what happens. In most areas of the country, organized crime operate clandestine repeaters and use radios for their illicit activities. I have a friend who is a taxi driver in Guerrero, where there are many checkpoints, and he uses a handheld transceiver for his taxi company communications. He recently told me that he has been stopped a these checkpoints, where, upon seeing the handheld, have briefly confiscated it, checking to see if is set to receive any prohibited frequencies( i.e. police and military channels). Federal Police and the military now mostly use an encrypted TETRA system, however the vast majority of local municipal police agencies still use VHF analog repeaters and simplex systems. If you understand fluent Spanish, a scanner can provide an unlimited amount of analog transmissions to monitor and enjoy. In the rainy season, listening to the national power companies (CFE) multiple VHF analog repeaters can really be informative to find out where the power is out, highways washed away, and other road blockages. However, is bringing a scanner really worth the risk of ruining your vacation?