[RTuesday]

I've been using Telcel, it does the job for a local phone. See my previous messages in this section for how it can be refilled online to keep it active (each refill is only 2 months but rolls over balances) and other stuff about Telcel.

Incoming calls, even international, are free in the receiver's home area (changed a year or so ago). Forwarding calls to Mexico from Europe can get expensive - over a Euro a minute on Movistar ES (although still cheaper than roaming).

I don't know the international call cost on Telcel to Europe - the base tariff is about 12 pesos (nearly a dollar) per min even to the US, so you can be sure it's not cheap. There are some "pay per call" deals but they only apply to the US/Canada.

So simply using a local SIM in place of the Spanish one is going to save her some money over the 2,30 Euro/min roaming rate, but it'll still work out very expensive if she has lots of calls to/from Spain.

To really be cheap, you'll need something more creative (maybe a VOIP account with Spanish and US DID numbers, and a low cost route out to Mexico mobile...).

But the easiest option would be to send the Spanish phone direct to voicemail when in Mexico - maybe leave the sim in a spare phone so she gets notifications of messages left and can receive texts - then pick up the messages and make outgoing calls from Mexico with callback to the Mexico sim (callbackworld for example is US 24c/min to a Spanish landline, 41c Spanish mobile) or a calling card. By not forwarding the Spanish number she can explain her absence on the outgoing message, and also not be woken up really early when a european calls her in their morning!