Of course it goes in nighttime.
You need to have some kind of ´permit´/letter from your parents in any case, not just for this ferry.
The rules for ferry are to be found on their website-its Scandinavia, so there will first be an enormous amount of what you cannot do, like buy/drink alco. The comes the rest.
Yes I know that. But what counts as a day ferry? The ferry from Stockholm to Tallinn takes 16 hours so it might go through the night.
Well, then you need to look up the timetable first.
You need to contact Tallink and ask.
https://en.tallink.com/en/contact-us
Yes I know that. But what counts as a day ferry? The ferry from Stockholm to Tallinn takes 16 hours so it might go through the night.
You can travel on a day ferry on Tallink if you have a written consent from your legal guardian, see info under Age Regulation.
https://en.tallink.com/en/good-to-know#16658622