Thanks for the information.
It would also be good to know how long the package is kept at the post office. I would receive it in Trondheim approximately 3 weeks after it was sent to Hungary.

Thank you, Zoltán Somogyi

The Postal service has a service called poste restante, which means left at the post office to pick up. You would then need to address your package to a specific post office. You can find the post offices here: https://www.posten.no/kart. Let’s say you want the post office in the centre of Trondheim. Your address in this case would be

Zoltán Somogyi
Poste restante
Trondheim Sentrum Post i Butikk
Bunnpris Munkegaten
Munkegata 48, 7011 Trondheim
Norway

As for returning your bicycle, I guess the trouble is packaging it. Probably a bike shop would have a leftover cardboard bike box you could have. I will put you in contact with the local randonneurs to see if they can help you with that.

My name is Zoltán Somogyi, a Hungarian Randonneur. This month, I intend to cycle through Europe from Hungary to Trondheim. I would like to receive advice on two problems. First, I want to send a package to Trondheim by post before departure. Does Norwegian Post have a service called «Package left in the post» that I could pick up at a local post office 2-3 weeks after my departure when I arrive there? Or does someone have another idea?
The other is to return my bicycle to Hungary. I travel back from Trondheim to Oslo by train and then by plane to Hungary. How can I post my bike in Trondheim? Or should I take it with me on the train and the plane? Even with this solution, I would have to create some kind of package.
I will be grateful for any good advice or tips.
Thank you, Zoltán Somogyi
zoltan.somogyi1@veolia.com