Entering Slovenia is usually a straightforward procedure. If you’re arriving from an EU Schengen country, such as neighbouring Austria, Italy or Hungary, you will not have to show a passport or go through customs, no matter which nationality you are. If you're coming from any non-Schengen country, ie outside of the EU but also including Croatia, full border procedures apply.
Goods brought in and out of countries within the EU incur no additional taxes, provided duty has been paid somewhere within the EU and the goods are for personal use. Duty-free shopping is only available if you're leaving the EU.
Duty-free allowances (for anyone aged over 17) arriving from non-EU countries:
EU citizens need only produce their national identity cards on arrival for stays of up to three months. Everyone else entering Slovenia must have a valid passport.
Generally not required for tourist stays up to 90 days (or at all for EU nationals); some nationalities will need an entry visa.