Any foreign citizen, who comes to visit Ukraine can stay In Ukraine either for the term specified in visa or for 90 days visa-free (for the citizens of those countries with whom Ukraine has the visa-free regime). In Both cases, a foreign citizen can stay in Ukraine maximined within the last 180 days` period.
How to calculate 90-days of stay in Ukraine properly?
When this 90 days term expires foreign citizen has basically two options:
1) leave Ukraine with the right to re-enter after 90 days period;2) extend a stay in Ukraine.
Legislation of Ukraine prescribes the following options for the extension of stay of any foreign citizen:
1) get temporary residence permit;2) get permanent residence permit;3) get a decision of migration service office on permission to extend the stay on the territory of Ukraine.
Such a decision (3) is issued only when there are some serious grounds, such as illness, pregnancy or childbearing, illness of the member of family who has to be taken care of, waiting for the official documents being issued (such as immigration permit, acceptance into the citizenship of Ukraine etc.), force majeure events that do not allow you to leave Ukraine within the legally permitted terms of stay. All the aforesaid fact shall be proved with the respective documents.
The motion for extension of stay on the territory of Ukraine shall be submitted to the local migration service office and at least in three days before the expiry of the visa or 90 days. When the migration service body grant you with the decision on extension of the term of stay on the territory of Ukraine, the special stamp is inserted in your passport document. The maximum period of extension is 90 calendar days. If you leave Ukraine prior the 90 days` period you will not be permitted to re-enter Ukraine, so you will have to wait either for 90 days or get the new visa.