Short term accommodation
"Gives you the roof over your head when you arrive!"
HOAS Guest Rooms
Foundation for student Housing in the Helsinki, HOAS has a Guest Room service for researchers, students, and other people who need temporary accommodation. The Guest Rooms are located in Viikki and Lauttasaari, both in Helsinki. More information and an application form can be found in here (hoas.fi)
Forenom (forenom.fi) is a privately owned company which offers furnished flat and also single rooms in shared apartments for either short or long term needs. The rent usually includes furniture, electricity, water and TV, pillows, blankets (without bed linen) and dishes. As a student you can e.g. gather up group of friends and apply apartment together.
Email: asuntotoimisto [at] forenom [dot] fi
Wimdu (wimdu.fi) is online platform for private accommodation of all kinds, bringing together travelers with hosts from all over the world. Good option to look for short term accommodation.
If you do not have an apartment before arriving in Finland, be sure to make a reservation for a hostel early enough! The hostels are often fully booked in early September. You can search for a hostel e.g. by following this link hostellit (hostellit.fi).
Couch-surfing for the adventurous
You can also try couch-surfing (couchsurfing.org), a volunteer-based network for accommodation,
Other types of accommodation: Apartment hotels, hotels, hostels
There are plenty of other accommodation solutions available within the Helsinki Metropolitan Area suitable for short term needs. Apartment hotels, Bed & Breakfast providers, hotels, hostels etc.
The City of Helsinki website has gathered a good list of hotels and other accommodation types on its Visit Helsinki pages. (visithelsinki.fi)
The City of Espoo has an accommodation search tool on their website Visit Espoo. (visitespoo.fi)