Você não precisa de visto se ficar 30 dias na Mongólia. De Ministério das Relações Exteriores da Mongólia :
Within the framework of the 100 days of the intensification of economy the Government of Mongolia approved a list of 42 countries with a visa free access to Mongolia. According to this decision nationals of these countries are entitled with the visa-free stay for up to 30 days for tourist and short business trips from June 25, 2014 till 31st December 2015.
The list includes the following countries: Republic of Austria, Principality of Andorra...... Italian Republic, Republic of Ireland.... Republic of Estonia.