Is it easy to get prepaid SIMs in the US/Canada?

this answer is a bit late, but I thought it would be useful to others who may be asking a similar question.

I recently returned from a trip to the USA.

It is easy to buy a Sim Card over the counter, and you can get one from any of the carriers

The largest being:

• Verizon (CDMA) (Largest)
• AT&T (GSM) (Largest 4G at time of post)
• Sprint (CDMA) (Update No Prepaid)
• T-Mobile (GSM)

Most will have prepay options, but it may be cheaper to get the Pay Monthly options if you are there for close to a month (or more).

Most of them have a $1 -$3 per day type prepay plans Or $40-$50 per month unlimited prepay plans.

Which one you chose depends on which cities you are visiting (different coverages) and what kind of phone usage you think you will need (calling, txting, data) are you using a smartphone? do you need 3G or 4G?

If you have a smartphone, a good way to save on data charges is to connect to free wifi hotspots at McDonalds and Starbucks which are plentiful in the major centers (both USA and Canada).

The USA sim card will work in Canada but you will be subject to roaming charges

Conclusion
My personal experience is that T-Mobile doesn't provide very good 3G coverage throughout the country, often falling back to 2G. So I would recommend going with AT&T if you have a GSM phone, and Verizon if you have a CDMA phone.

Update
For a full comparison of the carriers: http://cell-phone-providers-review.toptenreviews.com/

I can't vouch for Canada, but it should be incredibly easy in the US. Go to any AT&T or T-Mobile store and you can pick up a SIM for your phone with a variety of plans (data or not) to suit you.

In addition to the two major GSM carriers in the United States, AT&T and T-Mobile, you will find several mobile virtual network operators (MVNOs). These operators buy their network time from AT&T or T-Mobile, but have their own brand and customer support. Typically, you'll get more data for less money with these operators.

Two such operators are Red Pocket and Ptel. Red Pocket runs on the AT&T network and provides the widest coverage in the U.S. including Alaska and Hawaii. Ptel operates on the T-Mobile network and is the easiest to use in terms of set-up. You just put their SIM in your unlocked phone and go. No need to mess with APN settings and the like. Both operators offer generous unlimited plans for voice, text and data and also offer international calling packages.

I suggest you shop around as there are lots of third party sites that will deliver a SIM to you in your home country before you arrive in the U.S. In most cases, you will also know your U.S. phone number before you arrive so you can share with your friends and family. You should NOT have to provide passport information or photos. So far the U.S. still allows anonymous prepaid phone use.

FULL DISCLOSURE - We operate one such third party site (http://secure.travelmobile.biz), but if you look through answers here on StackExchange you'll find other options as well.

The procedure for buying prepaid SIM cards in Canada and the US are exactly the same. You require your passport, and money. Your card is activated before you leave the store.

Most people have long, ongoing discussions about how one network has superior coverage then the other, but really they're all the same to most tourists that are in major urban centers. The only thing I would warn about is whether or not your unlocked phone is compatible with AWS networks.

In Canada Wind, Moblicity, and Public mobile all run on the AWS network which requires a AWS or pentaband phone. So double check if your frequencies work with then (iphone for instance doesn't work on them) Same with T-Mobile in the US.

You will notice that prepaid is a lot more prominent in Canada then it is in Europe and most parts of Asia, and the registration process is much easier.

Happy travels!

I've been using Simple Mobile prepaid SIM cards over the last few trips and works great in New York. You can pick one up at the airport, I generally order from Arieli mobile and they ship it to me.