Post in Finland is handled by a government owned company named POSTI (former ITELLA).
The main post office (posti/post) in Turku is at Eerikinkatu 19. It is open Mon–Fri 8.00–20.00, Sat 10.00-14.00.
Poste Restante is located at the Main Post Office in Turku, open Mon–Fri 10.00–14.00.
For information about opening hours, postal codes and prices, you can call the national postal service line 0200 71000, Mon–Fri 8.00–20.00 and Sat 9.00–14.00 (local call charge). More information can be found also here
Stamps can be bought at most kiosks, bookshops and department stores. A first class letter (less than 50 g) costs 1,10 €, second class 1 € inside Finland.
The standard way of writing a Finnish address is:
Street name and number (also apt. number)
Postal code, City
Change of address refers to a notification where a mail recipient informs Posti that the address is about to expire and communicates the new address. Change of address is free of charge. Based on the change of address, Posti will forward to the new address all letter items and universal service parcels (Postal Parcels) sent to the old address, unless agreed otherwise with the sender.
Online is the most convenient way of carrying out a change of address. You can log into the service using your online bank ID, a Posti user ID or an identity card with a chip.
You can also order the service using a printed form and the accompanying return envelope. Forms are available at postal outlets.
You can notify a change of address by calling at 0295 535 535 (local call charge/mobile charge) Monday-Friday 8 a.m.-4 p.m.