Easy to book online, no upfront payment which was great for us as we were down one starter due to a Segway accident in Strasbourg. Dani our guide was really enthusiastic, she had a very good knowledge of Finnish history and the features of the landmarks we visited and in addition spoke perfect English. The trip was very well organised, bikes were in very good condition, the cycling itself was on cycle paths about 95% of the time (and you get plenty of warning when you won't be on paths) and really nothing to talk about concerning hills (anyone with a modicum of fitness could do the tour). Do this at the start of your stay in Helsinki - far better than a hop on hop off bus, you will get to know the city within 3 hours or so and you will burn a few calories to boot.
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