The Baltic Sea and the Helsinki archipelago deserve a day in your (summer) itinerary. There are over 300 islands in Helsinki alone, and the city is also a gateway to the wider Gulf of Finland. Extensive ferry connections make it easy to hop from one island to another – though it's worth knowing that only the Suomenlinna ferry runs year-round. The routes to Vallisaari, Lonna and Pihlajasaari are seasonal water buses that typically operate from May to September.
The fortress island of Suomenlinna, a UNESCO site, is the most popular attraction for a reason, and it's reachable whatever the season. Nearby Vallisaari and Kuninkaansaari are for those looking to explore the archipelago beyond Suomenlinna. These former military islands offer nature trails, old fortifications, beaches and cafés. You can even spend the night in a tree tent.
Another island en route to Vallisaari is Lonna. This tiny, picturesque island is home to a public sauna and a restaurant – perfect for a laid-back summer day out.
For a beach day, Pihlajasaari is a local favourite, especially among families. The island is only a 10-minute ferry ride from the mainland in summer, but its beautiful sandy beaches, old wooden villas and nature trails feel like a world away.
Helsinki's summer island restaurants are worth building a trip around. Take a short ferry to Skiffer Liuskaluoto for wood-fired pizza with a sea view, or head to HSS Paviljonki on Liuskasaari, a beloved terrace restaurant that's welcomed guests since 1949. For something grander, book a table at Restaurant NJK on Valkosaari, an early 1900s villa famous for its summer crayfish parties. Most of these restaurants run their own seasonal ferries from central piers, so check ahead before you go.
See MyHelsinki's guide to island restaurants for more options.