Ill be going to La Paz, Mexico this weekend and brought my detector with me. Thought about hitting the beaches. Didn't see any laws about it but didn't look that hard.
The week after that ill be in Purta verarta (sp) and will detect there.
I went through the border at Juarez, with several detectors in full view, and never had a problem. The border inspectors even saw them and asked "what're those?". My interpretter just said "Paso Tiempo" ("hobby"), and they waved us through.
If you ever did or do hear of anything about laws, it's probably more to do with historic monuments, shipwreck salvor stuff, etc... Not casual coin-hunting the beaches. That would be no different than the USA: If you asked enough bureaucrats here "can I treasure hunt in the USA" you'd probably find a few that would say "no", because they are thinking of ARPA, or Fed. protected land, Bodie, Shiloh, or legal finders-keepers cases, or something wierd. It would depend on how you worded the question.
All the major detector manufacturers have dealers in major cities down there, so detecting is not disallowed. Detectors are a common site on the tourist beaches.
Re: Going to La Paz, Mexico, Puerta Vallerta. Anyone ever detected there?
Well, I only had a day and a half in La Paz so i wanted to do a little bit of everything. I just happened to be there for the Baja 500 and the citys birthday. Big celebrations! I also managed to make it out to Todo Santos where the famous Hotel California was and El Cerritos where a nice beach was but didn't have time to detect it. There was a young crazy lady there that tried taking our food and was talking to herself until the waiter had to physically pick her up and take her away from our table. Not sure if she was on drugs or if something was wrong with her.
I did manage to get in about 45 minutes of detecting right in downtown La Paz. I guess it doesn't happen down there too often because there was a crowd on the seawall watching us and asking questions. A cute little girl was wanting to help us dig so we let her. It wasnt the serious detecting i wanted to do but it gave us a chance to mingle with the locals. I found about 6 different coins between talking and digging. One was 100 pesos which is 10 to 1 for us (10 bucks US). Apparently its no good because its too old. I guess they change out money every so often. I did find a big coin and was told it was over 50 years old but it was too encrusted to see the details. Ill tumble it when i get back. I wish i had more time because i only made it maybe 30 square feet and i didnt even get to the popular spot, oh well. We're off to Puerta Vallerta for 2 days and I will try to do some "serious" detecting this time.