Welcome to FlyerTalk.

The Ryanair website refer to six months' validity in order to use their online verification system. Otherwise your partner may* need to have their passport at the Ryanair visa check desk at the airport- allow extra time.

Spain is part of Schengen and follows the Schengen rules. For non-EU nationals, the passport must have a minimum of three months validity on the date of departure. Therefore her passport should be accepted for travel by Ryanair. Source: https://europa.eu/youreurope/citizen...s/index_en.htm

Ukrainian citizens do not require a visa to enter the Schengen area.

(*The Ryanair website really is terribly worded; it refers to 'non-EU/EEA nationals', but presumably UK nationals don't need a visa check?)