As a Golden Visa participant, will Greece tax me on all my worldwide income?

No. For the time being, Greek tax law doesn't impose tax on one's global income when you aren't a Greek fiscal resident. The fact of having the Golden Visa doesn't give you fiscal residency (for now, at least). Only property tax and (if applicable) income tax from rentals of the property. Nevertheless, in Greece, tax laws change a lot. So it's better to check this once in a while with your accountant also.

Your taxation will be based just on any Greek property. Worldwide income, right now, is irrelevant.

No, they don't tax you for the global income. You will be taxed only for the property you have in Greece, which is not much (around 300 euro per year).

According to article 4 of Law 4172/2013, an individual person is a tax resident of Greece, provided that: Greece is the permanent or principal residence, or habitual abode or center of vital interests, i.e., personal or economic or social ties; is a consular, diplomatic or public official or similar arrangements, similar public servant status or civil servant who is a Greek citizen and serves abroad. Second, there is having a physical presence in Greece for a period exceeding 183 days within any 12-month period, continuously or intermittently, is a tax resident in Greece for tax year during which the 12-month period is completed. Who also maintains the duty of proof of tax residence? From 2011 (L.3943 / 2011), the responsibility of proof of tax residence of the individual one has the person himself. So the person who has his tax domicile abroad will have to come to the foreign office of the foreigners and prove that he has his habitual residence and his vital interests abroad. If he does not come to the tax department or does not prove the above, he will be required to declare and be taxed in Greece for his worldwide income, even if he is a permanent resident abroad. According to the above, habitual residence, as we said above, is determined by the length of time an individual is in a country, i.e., at least 183 consecutive or intermittent days per year. So, in order to be considered as a tax resident of Greece or abroad, you must have previously lived there for at least 183 days. Residency is presumed to be routine unless the taxpayer provides evidence of his residence in another state.