Helsinki sits on a small peninsula of Finland, in amongst hundreds of tiny islands that dot the water. The town is easily navigable and it seems that most roads lead to water. The quay is home to the berths of a few major ships including Viking Line Cruises, Nordic Jet Lines, and the SuperSeaCat. Likewise, the seafront is faced by shops and restaurants and supports the daily flea- and farmers' market that sets up shop at the top of the quay. The busiest day seems to be Saturday when many more vendors come out to hawk handmade local souvenirs and wares. On most other days, t-shirts are sold from tents, while food, drink, and produce carts cater to passers-by, tourists, and regular everyday shoppers.
Though there is little lee from the wind coming off the water, the harbor is worth a trip. Market Square is great for collecting gifts for people back home or, like we did, buy a Finland hat to keep you warm after you egregiously underpacked. There are great views back towards the city, along with great shots of Helsinki Cathedral. You can look out to sea towards Suomenlinna, then walk over to anyone of many booths offering ferry rides out to the island fortress itself. If you are heading to Estonia, ships leave from the Olympiaterminaali on the west side and the Katajonakan on the east.