Daytrip from Tallin to Helsinki

We took a ferry boat from Helsinki to Tallinn and we opted to take a fast ferry (actually not a BIG boat at all) but the weather ended up being bad and the water had lots of waves so the "fast boat" had to go slow. If we do it again, we would not spend the extra money for a "fast boat" as the "slower" boat was bigger and took the waves much better. Both of these boats left for the downtown waterfront in Helsinki.

Also, RS Scandinavia Guide Book has sections on both Helsinki and Tallinn that might provide more information.

Both Viking and Silja have ferries and leave from the same harbors. There is no substantial difference in departure/arrival locations. The choice is really fast or not-so-fast ferry.

The helicopter service went out of business many years ago.

For a daytrip I would take the fast ferry. I hadn't thought about Charlie's problem of a bad weather day. I don't know if you have to decide three months in advance or can make plans when you actually have a read on the weather? We were in the Baltics end of July/early August and had one day where the wind really blew and waves were big. Other days were pretty much calm. Either ferry should drop you within easy walking distance of downtown. There is a second dock area within eyesight but a much longer walk from downtown. We walked from there because we hadn't picked up money on the ferry and couldn't find a convenient ATM - so no cash to take a bus, tram or taxi.

one more alternative - there is a helicopter tour from helsinki to talin, so possibly they have the samething in opposite direction.