I have been told that driving my private vehicle from California into Mexico is no big deal EXCEPT that I must have Mexican insurance. I am looking for specific recommendations about what to look for when buying the insurance - are all policies basically the same, is there an official agency that needs to underwrite the policies, are there exemptions to be wary of, etc etc. If you know of approximate cost of the policies, please post that as well.
The company I have used before, as recommended by "Mexico" Mike, Nelson Insurance is apparently no longer around, as evidenced by the broken link, and the fact that it's no longer listed on his review page.
His page also claims that insurance is not strictly required:
Auto insurance is not required to drive in Mexico. If you want to risk having an accident, losing your car, motorcycle or RV and being thrown in jail to save a couple of hundred dollars, that is your right. Personally, I think it is foolish not to buy auto, RV or motorcycle insurance from a Mexican company to drive in Mexico.
You see the statement that "Mexico requires automobile insurance" on numerous web sites. Honestly, that is not true. I want you to get insurance, but I also want to tell you the truth. Mexico is one of 4 countries in this hemisphere that do not require auto liability insurance nationally.
I do know that it's not required for Mexicans to have auto insurance, but I've also heard that it is required for foreigners to have auto insurance when registering their vehicle at Mexican customs. I've always had insurance when I entered, so have never tested this requirement personally.
And as cheap as Mexican auto insurance is (or has been for me, with the company that's no longer around), I think you'd be foolish not to buy insurance, too.
And finally, one thing to be aware of when buying Mexican Auto insurance is that most Mexican auto insurance policies work differently than U.S. insurance policies. Where as part of a U.S. policy, you generally select a deductible, which in turn affects your premium, most Mexican policies simply pay a percentage of damages, up to a maximum. I have seen some Mexican policies that operate more like U.S. policies, but they are hard to find (I think Nelson used to offer those).
You can buy a policy online through AAA. See this link. It does not appear that you have to be an AAA member to buy a policy. The cost depends on your car, length of your trip, what limits you want, etc; it should be easy to see a quote.
I haven't done this myself, and I also can't speak to how competitive the price is, but I have had my regular auto policy through AAA for several years and have found them to have good service and be very competitively priced.
You might also ask your own auto insurance company. If they don't write Mexico policies themselves, they may be able to recommend another company.
Prices are regulated by the Mexican Governments, (Mostly federal laws), so it is best to compare services, as more or less service is the same price. Instant Mexico Auto Insurance has off street parking, assistance with claims in their office - not just giving you the carrier's phone number, drive through, lobby with clean restrooms.
There are things that can be added to policies, coverage amounts can be increased, more drivers, etc.
The underwriters must be an Mexican carrier who fall under Mexican laws. US companies do not fall under Mexican laws so the Government of Mexico has little control over them. A US company may fix your car but the problem is damages to other people.
In Mexico a car accident, liability, falls under the criminal law; You must show proof of ability to pay any liability, (A Mexican Insurance policy instantly shows that), or you could be thrown in jail until you post a bond which would cover the liability. By having a company that helps with claims, is basically a service specifically to help you; not a required service and not one you pay more for.
There was a case, I think in the state of Sonora, where the court ordered the carrier to pay more than the min liability required. I am guessing they had to pay 80,000 instead of 50,000 to a third party. Some agents are now selling policies of 300,000 because of that 3 year court case. Some carriers are in the process of rethinking the min they sell. But, the driver of the vehicle only needs to show the police the insurance coverage paper from a Mexican carrier.