Is this eSIM valid for neighboring EU countries like Poland or Romania?

 This specific plan is valid only within Ukraine (or, if it's a regional plan, you'd say "Yes"). This is the most important question. 90% of travelers enter overland from Poland (Krakow/Rzeszów) or Romania (Bucharest). Your EU roaming plan will stop at the border, leaving you without a connection. We highly recommend our Europe Regional eSIM, which covers both Poland, Romania, and Ukraine.