Sorry about that. Yes, two SIMs is definitely going to give you the biggest bang for your buck.

As a general rule you should buy a SIM card that gives you a phone number in the country you are travelling to: the local number gives you the best local rates. So that means separate SIMs for the US and Mexico.

It’s usually best to buy from a North American distributor and have it shipped to your home before you leave. (The SIMs distributed in country are geared towards locals and have high rates for calls back to North America. As a general rule, cards distributed in North America are geared towards us, and have better rates for calling home.)

It’s most convenient if you have a data plan on the same SIM. (Especially if you can tether any devices through your phone.) Most data plans are for a month, although I am seeing a growing number of one day plans. It looks to me like one day plans are geared towards checking your email. If you’re a power user, it probably makes sense to get a one month plan – even if your vacation is only a week or two - since you may blow past the one day limit. (If in doubt of your usage, I’d recommend investing in a larger plan. The down side is that you might pay $20 per month unnecessarily, but overage tends to be pretty high when you are travelling, so that one large email attachment can end up costing you a lot more than you expect. We had a couple of tech entrepreneurs in the office yesterday who are working on a mobile app that would tell you when you are getting close to your data limits – no matter where you roam – but there’s nothing out there that I’m aware of that is currently cheap and reliable for an individual consumer.)

Getting a little more specific, since you are planning ahead, our Mexico plan is a good fit for you. Our US SIM is geared towards Canadians. It has good voice rates in the US and back to Canada. The data rates are below roaming rates, but really only good for checking your email. (We’re working on a US data plan for the power user. )

The good news is that America has lots of SIMs available with good data plans. I’m sure some of the forum members can recommend some options.

Please let me know if you have any other questions.