Departure
We took an overnight flight from Hong Kong Airport to Northern Europe.
This was my second time going to Europe. I feel that taking an overnight flight to Europe works best: sleep on the plane, wake up the next morning, and you are there without wasting a day.
The blueberry juice that so many people praise on Instagram was just so-so to me. I liked the apple juice more.

After landing, we walked along the corridor.

There were toilets, smoking areas, and drinking fountains along the way.
Even at 6 in the morning, the immigration queue was already very long.

After clearing customs, we were officially inside the airport.
We asked the information centre where to take the metro, then went to the convenience store to buy a one-day pass.
Note
The Helsinki one-day pass has several zone sets.
If you do not want the hassle, just buy Zone ABC, which also covers the airport.
See this website for details: HSL area and zones
Turn right at the airport and you will see the metro signs. The whole route is indoors, so do not go outside.
Here is what it looked like at 7 in the morning when I went out for a cigarette.

Down at the metro station.

There was no space for luggage on the train, so if you see a seat, take it. Otherwise, you have to go up a few steps before there are seats.
Heading to the City Centre
After getting off at Pasila station and going outside:

We crossed the road and waited at the stop.
The whole sky was full of birds.

Then we took tram number 2. It felt a bit like Hong Kong Light Rail.
Helsinki trams cover almost the entire city centre. If you have bought an ABC Day Pass, you basically do not need to buy another ticket.
This is what the tram looked like inside.
The display shows the next stop. Press the bell before getting off. When boarding, scan the QR code on the blue machine on the left.

There is a small button by the door. Press it and the door opens.

Kauppatori Open-Air Market
We went to the open-air market for breakfast and got off at the Kauppatori stop.
https://maps.app.goo.gl/PDwJ7j8Yee45iaAm8

The nearby scenery:

Unfortunately, when we arrived at 9, the stalls still had not opened.
Panorama:

So I suggest going to the central railway station first, putting your luggage in a locker, and then walking to the open-air market.
Since the stalls were not open yet, we decided to go to the central railway station first, put our luggage in a locker, and then come back for breakfast.
Central Railway Station Lockers
Because there are metro stations near the railway station as well, we took the wrong way, but it turned out fine.
There was a free toilet there.

Go back up and walk to the railway station next door. Remember, you do not need to go downstairs at the railway station.
For the lockers, turn left as soon as you enter and walk straight. You will pass through to the outside, then go back in and see the locker sign. The lockers are downstairs.
There is a toilet next to the lockers, but it costs money.
Here is an extra photo of the railway station.

After that, we walked back to the old market hall for breakfast.
Photos from along the way:

Brunch
We arrived at the old market hall.

There was a restaurant in the middle. I heard it was popular on Instagram, so we tried it.

This is what we ordered.

Drinks and cutlery are picked up outside.
We were lucky to run into people singing hymns.
After eating, we took the ferry to Suomenlinna.
The ferry had not arrived yet when we reached the pier, so we walked around first.

Suomenlinna
After that, we spent the whole afternoon at Suomenlinna.

I share more photos and details here: Suomenlinna
We got back to Helsinki at 5 in the afternoon.

Sauna
Since we had not showered for the whole day, we decided to go shower and use the sauna.

A few tips:
Remember to bring your own towel and swimwear. Renting them is very expensive.
The lockers inside cannot fit luggage.
Remember to shower properly before going into the sauna room.
You can put your glasses on the shelf by the door before entering the sauna room. Also, both the sauna and the pool are outdoors, and even the nearest sauna room requires a short walk.
Take note if you are going in winter.
After finishing, we decided to go for dinner. We went for Vietnamese food.
I do not understand why there was fried rice that did not seem Vietnamese 🤣

All I can say is that the meal was very ordinary.
Finally, we took the legendary Santa Claus train to meet Santa Claus.
For the Santa Claus train, I personally would not recommend taking it if you cannot book a bed.
I will talk about the Santa Claus train here: Santa Claus Express