Mexico

Basics
Mexico has 4 mobile operators: Mexico is Carlos Slim country. The telco tycoon has made his fortune here controlling the landline market with Telmex and the mobile market with América Móvil. Its mobile provider is not called Claro like anywhere else, but Telcel in Mexico. It has a huge market share of more than 2/3 of the nation's subscribers.
 * Telcel (owned by América Móvil)
 * Movistar (owned by Telefónica)
 * Iusacell (incl. Unefon, bought by AT&T)
 * Nextel (bought by AT&T)

Telcel has the best coverage but can suffer from congestion. Movistar is the only viable competitor with a reasonable coverage, while Iusacell and Nextel have very limited coverage at low rates. In 2015 AT&T acquired both Iusacell and Nextel. It is expected that they will merge these brands and build a 3rd major provider.

2G and 3G are on 850 and 1900 MHz on all operators except Nextel, while 4G has started with Telcel, Movistar and Nextel on 1700 MHz. Nextel has 3G and 4G only, both on 1700 MHz. Telcel covers 65 % by LTE, Movistar around 50 towns and Nextel only a few towns.

You can ge a prepaid SIM card, which is called chip anywhere in Mexico from the major operators and their outlets for $150-200 (that is Mexican Peso, not US$) with some credit on it. No need to show an ID or give any address, but to be safe, take it with you when you buy the chip. Top-ups can be made anywhere by topup cards or direct topup giving the phone number at the checkout of supermarkets.

Be aware that to reach a mobile phone from outside of Mexico for some reason a 1 must be added before the area code. So it is: +52 1.

Telcel
Telcel is the top dog in the country (see above). Its prepaid line is called Amigo. It has the best coverage on 2G, 3G and 4G/LTE at the highest rates. 4G/LTE is free for prepaid where available. Telcel 3G coverage map Telcel 4G coverage map. 4G/LTE coverage in 2015 has reached 65.5%.

Availability
SIM cards are can be bought from local Telcel dealers and outlets you'll find almost everywhere in the country or here for $149 with $50-75 credit, depending on promotion. It doesn't matter which tariff line you are on for data.

Top ups are supposedly possible to be done online, but foreign credit cards are often not accepted. Otherwise, the ubiquitous Oxxo stores throughout Mexico all sell top ups for cash only. You hand over your phone number to the cashier and it’s automatically added to your phone. Amounts of $20-500 are available, all top-ups of $100 have a validity of 60 days.

SIM sizes
Mini-SIMs exist. Nano SIMs and micro SIM are sometimes available as well. Most dealers will just cut an ordinary mini SIM to micro SIM size in case micro SIMs are not available.

Data feature packs
Default data rate is expensive $2 per MB on all prepaid tariffs. So switch to data packs bought through SMS or online on your account. To buy any pack, send an SMS to the number 5050 contaning the activation code for about $1 fee. You will receive a free confirmation message in Spanish after sending the message. Overuse or out of bundle use will be charged by the default rate. You can check data pack by *264.

More info

 * Tethering is available without extra charges
 * APN: internet.itelcel.com
 * Username webgprs
 * Password: webgprs2002
 * Website: http://www.telcel.com (mostly in Spanish)

Movistar
Movistar is the only real competitor of Telcel in Mexico. Though it has not their coverage, it gives out data cheaper and suffers from less congestion. so data rates can be faster: Movistar 2G 3G coverage map

Availability
The starter pack called chip prepago can be bought in any Movistar dealer in Mexico, with most airports having one Movistar shop locator. The prepaid SIM card costs $200 and comes with $50 worth of credit. Top ups can be made in a lot of stores: Recharges of $10-500 are available giving you 10 to 90 days of validity.

Data feature packs
Default data rate is $0.85 per MB on the standard plan. They offer a variety of data packages:

Combo internet (mainly for email and social messengers) The allowed apps are: Facebook, Twitter, Whatsapp, Hotmail, Yahoo!Mail, Gmail.
 * 3 days, 250 MB apps, $50
 * 7 days, 500 MB apps, 20 MB internet, $70
 * 30 days, 1 GB apps, 100 MB internet, $150

Or these regular data packages:

To activate either text the code to the respective number or dial #100#, choose "navega en internet", pick the pack you want and confirm selection. They will confirm this purchase by a text message.

More info

 * APN: internet.movistar.mx
 * Username and password: movistar
 * Website: http://www.movistar.com.mx in Spanish

Iusacell
Iusacell merged with Unefon some years ago building the 3rd operator in Mexico. At the beginning of 2015, they were acquired by US cellco giant AT&T togehter with Nextel. They operate a hybrid non-compatible CDMA and GSM network. Their GSM coverage is much less than Telcel or Movistar: Iusacell Coverage map. So make a network scan before you buy a SIM. It is expected that they will be merged with Nextel soon.

Availability
Their SIM cards called "VIVA prepago" are available in their stores: Iusacell store locator for $100-150. Top ups can be made in a lot of supermarkets and banks from $15 - $1000 giving 15 to 90 days of validity. For the first topup of $50 or more you receive 50 MB extra.

Default data rate
The standard rate outside of packages is $35.80 for the first 2.5 MB per month. Every following MB will be billed with $1.19. So better buy packages.

Data feature packs
To purchase data on packages, you need to activate combined packages Iusacell calls VIVAPacks. Overuse is charged at $2 per MB. All packages are valid for 30 days. To activate, text 'ALTA' to 6611.
 * Vivapack 150: $150 including 300 MB data, 20 domestic SMS and $200 airtime, code: VP1
 * Vivapack 200: $200 including 500 MB data, 40 domestic SMS and $300 airtime, code: VP2
 * Vivapack 300: $300 including 1 GB data, 60 domestic SMS and $450 airtime, code: VP3
 * Vivapack 500: $500 including 3 GB data, 100 domestic SMS and $750 airtime, code: VP4

More Info

 * APN: web.iusacellgsm.mx
 * Username and password: iusacellgsm
 * Website: http://www.iusacell.com.mx/ in Spanish

Unefon
Unefon merged with Iusacell in 2007, but kept its own brand. Back then, it was a CDMA-only operator, not compatible with GSM. Soon they began to migrate from CDMA to GSM thanks to own refarming and a roaming agreement with Iusacell. In 2015 both were acquired together with Nextel (see below) by AT&T and its expected that they are going to form one network soon. Their coverage is now in GSM-only and identical to Iusacell (detailed coverage map), but much less than Telmex and no 4G/LTE yet.

Availability
Their SIM card called chip is sold for around $50-150 with $100 credit loaded in Coppel, Elektra, Famsa and Walmart stores. It can be topped up in many stores shown here.

Data feature packs
Their new tariff line is called Unefon Flex and includes heavily discounted rates valid in Mexico and for roaming in the US and even in Canada.

The top-ups, rates and validities are identical to Nextel Libre (see below). So it can be expected that Nextel and Unefone will merged soon to one brand. Have in mind that Unefon uses Iusacell's 3G on 850 and 1900 MHz, while Nextel is still on the 1700 MHz AWS band.

More info

 * APN: web.iusacellgsm.mx
 * Website: http://www.unefon.com.mx/

Nextel
Nextel is the smallest operator in the country. It has a hybrid network with the non-compatible iDEN technology and a 3G/4G network only on GSM with no fallback to 2G. So coverage is worse than the other operators, but can be great, if you use it at one location you have connection. Nextel focuses on triple-play products and has both 3G and 4G only on the AWS frequency of 1700 Mhz: Nextel Coverage list. 4G/LTE is open for prepaid. Be sure to have coverage before you buy a SIM card.

In 2015 Nextel was bought by AT&T. It is expected that it will be united with Iusacell/Unefone. They started by introducing a new tariff line called "Libre" without roaming fees in the US.

Availability
Their prepaid SIM cards are available in their stores (store locator). Top ups can be made in a lot of supermarkets and banks (list of stores).
 * SIM 100 Nextel RED 4G: $100 with 100 MB valid for 7 days
 * SIM 200 Nextel RED 4G: $200 with 200 MB valid for 14 days
 * SIM 500 Nextel RED 4G: $500 with 500 MB valid for 30 days

Data feature packs
The standard rate outside of packages is $2 per MB So buy one of there packages: Activation by texting code to 2020. Overuse is charged by the default rate.

Nextel Libre
Their new tariff line called Libre has heavily discounted rates for roaming in the US on AT&T network. Take care that the frequencies of AT&T in the US and Nextel in Mexico differ. Both tariffs lines are valid in the US roaming on AT&T too. On Nextel Libre you will pay $2.50 for roaming on top. This is skipped on Nextel Libre USA for top ups of $150 or more. Free Whatsapp is included in all plans of $150 and more, free Facebook and Twitter in all plans of $200 and more. The first change of Libre lines is free, from the 2nd it will charged at $10. To change to Nextel Libre USA text 'cambio plan usa', to change to Nextel Libre text 'cambio plan nacional' to 6060. These plans are very similar to Unefone's new plans (see above).

More Info

 * APN: wap.nexteldata.com.mx /or/ modem.nexteldata.com.mx
 * Website: http://www.nextel.com.mx in Spanish