by sea
Hanko is primary notable as a port.
The daily car ferry to Rostock, Germany is now operated by Scandlines (http://www.scandlines.com) and has services only four times in the week.
Navirail (http://navirail.com) offers passenger and car services to Paldiski, Estonia.
The sail boat harbor is operating in the summer and very popular.
by train or by bus
There is limited commuter train service from Karjaa, on the main Helsinki-Turku line, or you can opt for a direct bus from either city. All options take roughly two hours.
by car
One can get to the Hanko peninsula along highway 25. The town is reached in 1,5 hours from Helsinki so it is suitable for a day trip.