Banks in Guatemala
Guatemala has a modern banking system with more than 25 banks regulated by the Bank of Guatemala (http://www.sib.gob.gt/). ATMs are available in all large towns in Guatemala. Using ATMs while traveling to take our local currency (Quetzal) is becoming more common. Unless you are traveling to small villages you should be able to use your Debit/Credit card at local ATMs. If you have trouble it is usually possible to go inside the bank and get help from the tellers.
Here is a short list of the larger Guatemalan Banks.
Banco Industrial (http://www.bi.com.gt/)
Banco Agromercantil (http://www.bam.com.gt/)
Banco America Central (http://www.bac.net/)
Banco GyT (http://www.gytcontinental.com.gt/)
Banco International (http://www.interbanco.com.gt/)
Opening a bank account in Guatemala is possible for foreigners IF you have a Guatemalan national to vouch for you. This is a new requirement started in 2011. You will need your passport, an electric or other utility bill from the place you live (it does not have to be in your name) and a local person to go with you to the bank and give you a personal reference. The Guatemalan must have a DPI which is the national ID card.
Guatemalan banks offer accounts in US Dollars or Guatemalan Quetzals
Travel Insurance for trips to Guatemala
While it is not a requirement it is a good idea to purchase travel insurance for your trip to Guatemala. Medical care is less expensive here in Guatemala than it is in most western countries but if you need emergency medical attention it can become expensive.
They both offer Free online price quotes, sign up and payment. We have personally used both companies when we travel and have made claims with both companies. They have always paid on time without any problems or hassles. You really should consider buying travel insurance before you make your next trip.