Originally Posted by
neos
Thanks for the info.
This would be a one-way crossing to Stockholm.
Since many people have written that Helsinki can get "boring"

after a while, I figured Turku would make for a nice day trip and we wouldn't have to take the train back to Helsinki.
But someone suggested that I should skip the Turku ferry and take the Helsinki one instead, since it leaves at 17:00 and would allow for more viewing while awake!

The idea of spending $$$ for a hotel in Turku only to have to wake up quite early doesn't strike me as very relaxing!
As we are also planning to visit Estonia, there's also the option of the Tallinn-Stockholm ferry.
So many options!
Being local, I am biased, but I hardly think Helsinki is very boring ;-)
Turku is good for one day but Helsinki does have far more things to do and see. Ferrywise, I love the early morning arrival to Stockholm on the night ferry -- the approach in the archipelago and the narrow shipping lane between rocky shores is quite spectacular. With any luck, you'll see swans out there.
Cheers,
T.