Alas, Helsinki's free Citybike system was suspended in 2010, although there are plans to bring it back. If you bring your own bike or rent one, you'll find an extensive network of bike routes within the city. Bikers are required by law to drive on the street next to cars unless a bike lane or integrated pedestrian/cyclists sidewalk runs next to it, and the police ticket cyclists breaking this rule. Bike lanes are clearly marked by street markings and blue traffic signs. Biking is also allowed on pedestrian streets.
Downtown bike lanes are typically on the sidewalks (instead of next to car lanes on the street) so be aware of pedestrians. Don't be afraid to ring your bell! Review your bike map carefully, as some bike routes will stop and require you to walk your bike or drive next to cars. There is also a journey planner for cycling [39]. Once you get out of the city centre, cycling is less complicated.
Public libraries often have free stocks of biking maps in Helsinki Metropolitan Area, so when they are not visible on tables it would be better to ask the map from the library staff.
If an ordinary bike isn't enough for you, you can also rent a cyclerickshaw (riksa) large enough for three from Riksavuokraus (tel. +358-50-5582525) in Eiranranta near Kaivopuisto. Prices start at €9/30 min, driver not included but available on request.