Fairly. There are a fair amount identical words or slight variations. Often similar words mean completely different things though.
Finnish: hallitus = government
Estonian: hallitus = mold
Finnish: ase = weapon
Estonian: ase = location (Finnish word 'asema' roughly means location/position)
Finnish: maakunta = province
Estonian: maakond = province
Still, the languages aren't similar enough to hold a fluid conversation. Switching to english is generally easier for both of us. We can catch on similar words to figure each other out, but straight up understanding is a long shot.
A lot of misunderstandings can also happen. Say, an Estonian says "Meil on suvel pulmad", which means "We have the wedding in summer", but a Finn can misunderstand that as "We have trouble in summer".