Visas are not required by passport holders from European Union, Albania, Andorra, Argentina, Australia, Azerbaijan, Belarus, Brazil, China, Ecuador, Georgia, Hong Kong, Iceland, Iran, Japan, Kazakhstan, Kuwait, Kyrgyzstan, Liechtenstein, Macau, Moldova, Monaco, Montenegro, New Zealand, Norway, Qatar, Russia, San Marino, Serbia, Singapore, South Korea, Switzerland, Tajikistan, Ukraine, United Arab Emirates, United Kingdom, United States, Uruguay, Uzbekistan and Vatican City.
Everyone else will need a visa, you may be able to get one on arrival but it is better, and easier, to get an evisa in advance.
E-visas cost US$6 for 21 days and US$30 for 120 days.
Passprt holders from African countries, except Algeria, Egypt, Morocco, South Africa and Tunisia, Afghanistan, Bangladesh, Nepal, Pakistan, Palestine, Sri Lanka, Syria and Yemen need to have a visa organised in advance through an embassy or consulate and you need an invitation.
Visa Information for Armenia