Postal charges to Canada and the US are fairly high ($1.25 for postcards and letters up to 20g), and they're higher still to Europe and Australasia ($1.50); expect delivery times of one to two weeks, the quickest deliveries, unsurprisingly, being those out of Buenos Aires. Express services ($5.75 for 20g to the US, $6 to Europe) save a few days, but items are tracked only as far as leaving the country so it's worth spending the $2 extra to send them registered post ( certificado ) as well. You should send any important letters or packets registered, as this increases the likelihood of them reaching their destination (though registered items do also go missing), or use the expensive but more reliable special-delivery EMS packet service ($25 for 250g to the US, $27 to Europe). Likewise, refrain from getting valuable items sent from home: normal post tends to come through fine, but any interesting-looking packet posted to you in Argentina should be sent registered. You are not permitted to seal envelopes with sticky tape: they must be gummed down (glue is usually available at the counter). It's worth noting that postal services in neighbouring Chile and Paraguay are both better value and more reliable, and that the Brazilian service is less expensive.

All post offices keep poste restante for up to a year. Items should be addressed clearly, with the recipient's surname in capital letters and underlined, followed by their first name in regular script, then "Poste Restante" or "Lista de Correos", Correo Central, followed by the rest of the address. Buenos Aires city is normally referred to as Capital Federal to distinguish it from its neighbouring province. Bring your passport to collect items ($1.50 fee per item). American Express also offers cardholders a mail collection service at their office in Buenos Aires. Address letters with your full name, followed by "Cliente de American Express".

For sending packages within Argentina , your best bet it to use the encomienda services offered by bus companies (seal boxes in brown paper to prevent casual theft by tampering). This isn't a door-to-door service like the post: the recipient must collect the package from its end destination (bring suitable ID). By addressing the package to yourself, this system makes an excellent and remarkably good-value way of reducing the weight in your pack whilst travelling, but be aware that companies usually keep an encomienda for only one month before returning it to its original destination. If sending an encomienda to Buenos Aires, check whether it gets held at the Retiro bus station (the most convenient) or at a bus depot elsewhere in the capital. Domestic rates for letters are reasonable ($0.75 for up to 150g), but the service is again quite slow - unsurprisingly perhaps, given the distances involved and the weak transport infrastructure. Calculate on a week for non-local letters to arrive.