Many trains - especially in the Baltics - don’t appear in the timetable in the app. That’s fine, you just add the journey manually. The app isn’t the definitive list of which trains you can take.

I suggest you check train times direct with the operators, and use these pages from Seat61 as a guide.

https://www.seat61.com/trains-and-routes/warsaw-to-vilnius-by-train.htm

https://www.seat61.com/trains-and-routes/vilnius-to-riga-by-train.htm

https://www.seat61.com/trains-and-routes/riga-to-tallinn-by-train.htm

You’ll need seat reservations on the international trains

If you’re travelling between Tallinn & Riga, it’s better to take a bus, unless you really want to take the train

Thank you for your interested 

No problem. I did a trip from Helsinki-Tallinn-Riga-Vilnius-Poland last summer and really enjoyed it. Let me know if you have further questions, and I’ll do my best to answer.

You are very kind.I will go for this summer to the baltic countries.I will can go Helsinki.Before I dont go this location.what do ı need to know to transfer to Helsinki?Do ı  need to pay extra ?

You'll get a discount on the ferry from Tallinn to Helsinki, No travel day needed, just a valid pass.

Thank you very much.

Hi everyone, jumping on this thread as it relates to my question.

I'm planning an Interrail trip through the Baltics this August (Vilnius, Klaipeda, Siauliai, Riga, Sigulda, Valga, Tallinn). The Interrail website says reservations aren't possible for 2nd class in the Baltics, but I'm unsure.
Somewhere else I read that it is possible (mandatory?) to reserve a seat only at the ticket office.
Has anyone recently travelled with Interrail in the Baltics? Did you need reservations?

Any tips on how to find out if reservations are required for specific trains would be greatly appreciated.

 Hello, I was worried about this issue, but they recommended these sites to me. I think there is no need for a reservation in this region. I think so because I did not come across it in the Railplanner application. You can review the guides on these sites. https://www.seat61.com/trains-and-routes/warsaw-to-vilnius-by-train.htm

https://www.seat61.com/trains-and-routes/vilnius-to-riga-by-train.htm

https://www.seat61.com/trains-and-routes/riga-to-tallinn-by-train.htm

Thank you :) 

As for the Warsaw->Vilnius train I recevied also this reply from LTG link customer service:

"The trip with Interrail/Eurail passport is possible after purchasing a non-refundable seat reservation, the reservation fee f is 5 euros per person. Currently, buying Eurail/Interrail tickets is available at ticket offices and on trains. We assure you that we are looking for more convenient solutions.
We are offering the option to prepare tickets and pay them by bank transfer - passengers also need to show their Interrail/Eurail passport during the trip.
If this offer is suitable for you, please clarify the travel details:
Date of travel
Route
Number of passengers
Just so you know, a non-refundable reservation fee of EUR 5 applies, which in this case will need to be paid by bank transfer, and we will send you the travel tickets.
Tickets are prepared for the entire route after payment of the reservation fee. The sale opens 30 days before the departure of the train, so we kindly invite you to apply in July."

Your welcome.have a nice trip.good lucky