Just a couple quick notes: a) USA has also 90 days business visas that are very easy to get. b) I can't vouch for all countries in the EU, but in many, you on

Just a couple quick notes: a) USA has also 90 days business visas that are very easy to get. b) I can't vouch for all countries in the EU, but in many, you only need to fill a report if you lived for more than 6 months there (168 days I think). So in your example, you would need to file tax in Germany, but for all income of the year (including the 2 months in Spain or Italy). It is different if you work for a company in Italy and Spain for those months, but if you are a 'nomad' for yourself, usually you only need to file in one country.