You need to be able to prove your nationality with a passport or a European national ID card. A driver license or a regular ID card is not valid.
In Swedish (swedish passport authority)
In English (Wikipedia)
No, but many guests make an effort to dress up (or down). Whatever takes your fancy. Anything goes!
No, you only pay for what you consume or buy on board such as food, drinks and duty free. Dance floors are free and open to all.
Smaller sound systems as “boom blasters”, computer sound systems etc are allowed in the cabins as long as you don’t disturb your neighbors, especially between 06.00-10:00 in the morning.
Swedish “‘Krona” and Euro as well as most major credit/charge cards are accepted on board. At the information desk (deck 6) you can change major foreign currencies to Krona or Euro.
The ship is a huge modern cruise liner and you will hardly notice that you are on a boat. On this cruise the ship will only be out on the open sea for one hour during the night. The remainder of the voyage will take place within the Stockholm archipelago.
More useful information can be found here
Friday-Sunday, September 8-10, 2017
M/S Romantika - 2000 capacity cruise liner
Tallink-Silja ferry terminal
18 years old when boarding.