There should normally be trains between those two countries (Białystok - Suwałki - Kaunas), at least on Friday, Saturday and Sunday, but they were still not operating because of COVID. Not sure if that has changed. The situation may change on 12 December, the start of the new timetable. Do check the timetables from about one month in advance on the DB website, which is updated much more frequent than the Interrail planner app. Unfortunately, Polish and Lithuanian railways are not really forthcoming with information.

Hi Ines,

yeah, there are still no cross border trains and with corona situation getting worse again I doubt that they will reintroduce them until December… you should take a bus in that case.

in general interrail will only pay off if you have a continuous pass for several weeks/months in the Baltics as prices are pretty cheap. Trains on most routes don’t run frequently and also moving from one country to another by train is more complicated and time consuming than by bus.

Watch the corona situation until your trip starts - in Latvia is now a lockdown for 4 weeks → there would be not much to do in that case in December as for long outdoor walks it gets early dark and also it is cold in December

Have a great trip!