Visa is required for citizens of Ukraine to visit Vietnam. Ukrainian nationals may have 2 options: Visit Vietnam embassy in Ukraine (Kiev) or apply for a visa on arrival to Vietnam from Ukraine online. Ukrainian citizens may apply for both tourist and business visa to Vietnam for the stay of 1 to 6 months from Ukraine. Please check this link for visa fee for Ukrainian citizens.

All the information for getting a visa from Vietnam embassy in Ukraine can be found here:http://www.vietnamembassy-ukraine.org/