Originally Posted by
MLTR
Since the origin and destination countries are both non Schengen, do I have to go through the custom/border control at HEL?
As long as you do not spend the night there, no and no.
Originally Posted by
MLTR
Do I need a transit visa?
AFAIK no, but refer to Finland's rules.
Originally Posted by
MLTR
Second, I have a tight connection time of 50 minutes. Do you think it's enough at HEL?
It's plenty enough time
if the first flight is on time.
With that said, you should always be prepared for the connection to break. There is simply no such thing as zero risk. That was true before Covid, and it still is true.