I'm using a prepaid Saunalahti service. I'm going to study abroad in Germany for 6 months and I would like to keep my Finland number. I looked for an answer for my case, but I couldn't find any discussion about it.
Vastauksen tähän kysymykseen jakoi irritus
Saunalahti Prepaid is valid 3 months from the first use and 12 months from the latest top up. So all you need to do is to make sure you top up your sim at least once before leaving Finland.
While in Germany, you can still receive calls and text with your Saunalahti Prepaid. However, sending text from Germany is not possible.
Making calls in Germany cost 0,066 €/min without a talk pack. If you have ordered Rajoitukseton 3G or Rajoitukseton 4G package, calls will be 0,03 €/min. Data transfer in Germany costs 7,44 €/GB regardless of any additional packages.
Roaming charges are about to change on 15th June 2018, so check Saunalahti Prepaid roaming price list (in Finnish) once it gets updated.