How to get from Helsinki airport to the ferry port in Katajanokka?
 

I will be arriving at Helsinki next Wednesday and would like to get to the ferry port to take a ferry to Tallinn on the same day. I am going to spend a couple days in Tallinn before I come back to Helsinki.
It seems to me there are several ferry piers in Katajanokka, am I correct?
From what I read, I could take bus 615 from the airport and transfer to Tram 4 to get to the pier. Is the transfer easy?
Should I book the ferry ticket before hand?

Thanks for your help.

This summer only slow boats leave from Katajanokka (Kanavaterminaali). If you want a fast one, they leave from Eteläsatama (South harbour, near the central market place) and Länsisatama (West harbour, across the city center further away). Nordic Jet Line from Katajanokka stopped traficing last spring. If you want a boat from South harbour the most simple way is to take a Finnair bus from the airport. It leaves you next to the main railway station. Then take a tram 3T, it takes you to the harbour. Here you can see the timetables and the harbours. MA-PE means Monday to Friday, LA is Saturday, SU is Sunday, and if there no mention of days it is every day. Here: http://www.viroweb.com/linkit/aikataulut.asp

Thank you for the very helpful information.
Do you know if I can check a small piece of luggage at the Etelasatama for several days. It is not a big deal if I have to take it to Tallinn with me but it will better if I don't have to.
Thanks.

I don´t remember if there are lockers or storage at Eteläsatama. BUT there are at the railway station, so you can leave it there before you take the tram. And you don´t have to book the boat in advance. The school holidays are over, it is not a weekend, and you don´t have a car.

A little addition, you don´t really need the tram. With no heavy bags you can walk, it is only 10-15 minutes to the South harbour from the railway station. BUT if you still want the tram (maybe it is raining) the 3T stop to the direction of the harbour is on the station´s side of the street when you step out from the railway station´s main door.

Thank you for the info.
I am hoping to walk but the weather forecast for next week includes some rain. I am really looking forward to my trip.
Cheers.