24 hours in Helsinki

Realistically you have an afternoon for sightseeing. Here's what our host recommends in Helsinki.

I had most of a day, and I'd recommend (from east to west) the Orthodox Cathedral, Lutheran Cathedral on Senate Square, a walk along the Esplanade (Kappeli's coffehouse is great), then a walk north on Mannerheiminte past the station to the National Museum.

The city museum (on Senate Square) was a disappointment. I didn't make it to less central sights like the island fortress or the Church in the Rock, and they might not be realistic with your time frame.

Depends what you are interested in - and also what time of year. (June means almost no night; December means almost no day.) I had less than half a day in June a few years ago and basically just wandered around the ferry port and market area, the center of town, plus took a ferry out to Suomenlinna, to see the fortress etc. It was pretty and scenic but not amazing.

Goggle New York Times, travel section, they have a whole series of "36 hours in.........." Actually very good for a quick hit.

Dic's list matchs my list as a good starting point for walking about. Add the Market Square which is a block from the Senate Square and a fun place to roam when the vendors are out. Market Square has anything from Russians selling fur caps to food stalls.

Look over Rick's list and pick what looks good to you. Most can be linked into a walking route with the Folk Museum and the Suomenlinna Fortress being obvious exceptions not being in City Center. The Fortress, accessable by ferry departing near the Market Square is a good several hour visit.
https://www.ricksteves.com/europe/finland/helsinki

▲▲▲ Temppeliaukio Church Awe-inspiring, copper-topped 1969 "Church in
the Rock."

▲▲ Uspenski Orthodox Cathedral Orthodoxy's most prodigious display
outside of Eastern Europe.

▲▲ Lutheran Cathedral Green-domed, 19th-century Neoclassical
masterpiece.

▲▲ Seurasaari Open-Air Folk Museum Island museum with 100 historic
buildings from Finland's farthest corners.

▲▲ Suomenlinna Fortress Helsinki's harbor island, sprinkled with
picnic spots, museums, and military history.

▲ Senate Square Consummate Neoclassical square, with Lutheran
Cathedral.

▲ Helsinki City Museum Tells the city's history well and in English.

▲ Ateneum, The National Gallery of Finland Largest collection of art
in Finland, including local favorites plus works by Cézanne, Chagall,
Gauguin, and Van Gogh.

▲ National Museum of Finland The scoop on Finland, featuring folk
costumes, an armory, czars, and thrones; the prehistory exhibit is
best.

▲ Sibelius Monument Stainless-steel sculptural tribute to Finland's
greatest composer.

▲ Design Museum Chronological look at Finland's impressive design
pedigree, plus cutting-edge temporary exhibits.

Thank you all so much for your quick reply! I should have added we will be there in a few weeks so looks like lots of daylight! 😃 This is all very helpful!
So we are staying overnight near the airport. Would you recommend taking a taxi to the city center or is there public transportation?

HEL to City Center (Train Station): https://www.finnair.com/fi/gb/information-services/at-the-airport/transportation

Train runs between HEL and the train station (I have not tried it but the train gets good reports): https://www.hsl.fi/en/timetables-and-routes/terminals/transport-links-helsinki-airport

FinnAir City Bus. Express with only one or two stops before train station. Good if you have baggage (under floor luggage compartment): https://www.pohjolanliikenne.fi/en/finnair-bus.html

Bus 615 (multiple stops but cheap): https://www.reittiopas.fi/