Commonly, foreigners from the EU, USA, UK, Canada, South Korea, Poland, and some other countries have the right to stay in Ukraine legally under the visa-waiver treaty (90 calendar days within the term of 180 days). To find out more about non-visa countries please follow this link. The nationals of other countries who want to stay in Ukraine temporarily need to get a visa. See the list of the countries that require obtaining an entry visa to Ukraine here.
The procedure of calculating 90 days of stay under the visa-waiver treaty in Ukraine is carried out by the relevant rules. You can get more info about it here.
Thus, how to extend your stay in Ukraine for more than 90 days?
Naturally, you must obtain a temporary residence permit (permission) in Ukraine. A temporary residence permit entitles a foreigner to reside legally in Ukraine with the right to prolong it. A temporary residence permit is an official document that gives the right to its holder to stay legally in Ukraine, leave and reenter the territory of Ukraine an unlimited number of times within the term of validity. Temporary residence permits’ validity term may vary from several months up to several years. For example, 3-year validity permits are given in case of the work or long-lasting international project, etc.
The law of Ukraine provides the following list of reasons for getting a temporary residence permit:
• Official employment;• Participation in international projects for technical support (such programs should be registered);• Performance of religious activity or invitation by a religious organization (officially registered and with permission to involve foreigners);• Employees of affiliated companies or representative offices of non-governmental organizations of foreign countries registered under the legal procedure in Ukraine;• Employees of representative offices of foreign business entities, banks;• Participants of international cultural, educational or scientific activities, given in international contracts of Ukraine or specific programs, participants of international or regional volunteer programs, or participation in work of Ukrainian organizations that are permitted to involve foreign volunteers (there is a special governmentally approved list of such organizations);• Education in Ukraine (not intended but already arranged);• Investing at least 100 000 EUR in Ukrainian business;• Marriage with the citizen of Ukraine.
Moreover, before applying for a temporary residence permit the applicant will have to get a D type visa (read more about visas to Ukraine).