The national postal system is called Correos de Nicaragua, and is surprisingly effective and reliable. Every city has at least one post office, often near the central plaza and adjacent to the telephone service (but not always). Legal-size letters and postcards cost about $0.70 to the United States, and a little more to Europe. Post offices in many cities have a gorgeous selection of stamps. Correos are open standard business hours (with some variations), almost always close during lunch, and are open until noon on Saturday.
To receive packages, have the sender use a padded envelope instead of a box, even if the shipment must be split into several pieces; keep the package as unassuming as possible, and try writing Dios Te Ama (God Loves You) on the envelope for a little help from above. In general, mail service to Nicaragua is reliable, even to remote areas.
Boxes, on the other hand, of whatever size, are routed through the aduana (customs). This means traipsing to their office at the airport in Managua  and enduring a horrific and uncaring bureaucracy intent on not giving you your goods. Most major international courier services have offices all over Nicaragua, including DHL and Federal Express, but they too are subject to the aduana.
The national phone company ENITEL (Empresa Nicaragüense de Telecomunicaciones, tel. 505/2278-3131, fax 505/2278-4012, www.enitel.com.ni ) was privatized in 2003 and is modernizing quickly under private ownership. Note that it is sometimes called TELCOR, its old name. A 24-hour ENITEL customer service operator is available by dialing 121.
Every major city has an ENITEL office, as do many small towns, and elsewhere you’ll find families offering their phones for pay instead. But these offices are quickly becoming obsolete in the age of cell phones, which have permeated into the poorest villages in just a year or two. You can also purchase phone cards that work in ENITEL and Publitel pay phones, located in any town bigger than Estelí .
Most ENITEL offices have fax machines. A two-page international fax may cost you $4–5; a local fax will cost about $1. Also check in copy shops, Internet providers, and post offices. Many local cybercafes offer VOIP calls as well; of note is the Llamadas Heladas chain, present in at least 29 locations.
In 2009, Nicaragua switched from a 7-digit to an 8-digit phone number system. All land lines earned an additional “2” at the beginning, and all cell phones took on an additional “8.” If you see a number with only seven digits, follow this formula.
Nicaragua ’s two networks are Claro and Movistar (formerly Bell South). Claro has better coverage nationwide (even in Waspám!) but calls are more expensive; Movistar works best in city centers but drops out while you’re on the road, but has more attractive pricing. Calls between networks are a bit more expensive than calls within networks, hardly enough to worry about, but enough for many Nicas to carry two cell phones.
Getting your own cell phone for travel is easy and inexpensive. Rent a cell phone from a booth in the airport in the luggage pick-up area (open during daylight business hours only), but it may make more sense to purchase a nearly-disposable cell phone (chiclero), available in Claro and Movistar outlets and at most gas stations for less than $20.
You can also put a local SIM card in your own dual-band cell phone (Nicaragua operates on the 800 and 900 Mhz frequencies); it’s easy to get a chip for either of Nicaragua’s two competing cell phone networks.
As you travel, you’ll notice there are little booths all over the nation that offer “recarga” of minutes, and many other stores can recharge your phone as well. Just give them your money and your cell number and they’ll dial it in; you’ll get an SMS within 60 seconds confirming the added time. C$250 is probably enough for a week’s worth of travel, depending on how long you chat or how often you phone home.
Cybercafes throughout the nation offer Internet calling, and Llamadas Heladas specializes in VOIP-based, cheap international calls. Connection quality can be dodgy, but with rates as low as $6 per hour to call the United States, Canada, or Europe, this is a great way to quickly get in touch back home. Of course you can also call home on skype.com or other broadband services, especially if you have a laptop, since many hotels now offer Wi-Fi in your room.