Accommodation

Finding a place to stay during your study exchange period is probably one of the most crucial things to do before you leave for Thessaloniki. The city is a very popular destination among Erasmus students, therefore you should not have any serious problems with finding suitable accommodation. There are hundreds of rooms offered by  private flat owners, private companies and hostels which are willing to offer a foreign student good deals for longer stays. On average, you should expect to pay around €150-350 per calendar month depending on the option you choose. I paid €250/month all inclusive in a private flat and it was considered expensive, but back then I did not know much about the Greek reality and I had nobody to help me. Here, I will try to give you personal advice on finding the right accommodation for you.

Aristotle University halls of residence

Since 2013 the University does not offer places in dormitories to Erasmus students, so don't even bother to ask/look for university owned halls of residence. The official reason for shutting down the dormitories for exchange students was the lack of interest among incoming students and their preference to pick private accommodation over living in the dorms. 

 Private accommodation

I am certain that you will not have any difficulties with finding a room/studio/flat in Thessaloniki. There are hundreds of posts on the Internet, the housing market in Thessaloniki is huge and you can find accommodation even last minute, let's say a week before arrival. It is necessary to tell your landlord the exact date of arrival so they can meet you in your new home in Thessaloniki, and to show you around. Signing a tenancy agreement in Greece between the landlord and the foreign student is something rather extraordinary. I was not asked to sign any papers, neither was any of my friends in Thessaloniki/Athens. Rent payment confirmation slips were given to me each month though. Prior to your arrival, you will most probably be asked to pay a deposit which will be refunded to you at the end of your tenancy (if you have not left any damages in the flat). 

MAKE SURE YOU ARRANGE A MEETING WITH YOUR LANDLORD BEFORE YOU LEAVE THE FLAT. I have heard of cases when the landlord never paid the deposit back. It may be a good idea to ask a member of the local Erasmus Student Network for assistance. I am sure they will be more than happy to help.
Generally, it is not uncommon for landlords in Thessaloniki to charge higher rent from foreign students. Renting out rooms for Erasmus students has become a lucrative business to some. Therefore, answering to an advert offering accommodation to Erasmus students,  you can expect to pay more than locals who find housing ads in the newspapers or on Greek websites. If you speak Greek, or know someone who does, I encourage you to try finding accommodation using local Greek sources. Sometimes, it is possible to find a studio flat for a price of monthly rent of a single room offered on stricte Erasmus forums or websites. 

Here are some websites with housing ads which you may find useful:

Aristotle University accommodation list - a list of landlords who offer accommodation for Erasmus students. 

Erasmus Thessaloniki Accommodation - self-catered, private rooms, studios and flats for Erasmus students.

Rent Rooms Thessaloniki - another private company which offers rooms for rent in Thessaloniki.

Spiti 24 - rooms, apartments for rent in Thessaloniki (in Greek).

Spitogatos - rooms, apartments for rent in Greece.

Greek Craigslist - classified ads, including housing, in Greece.

 Hostels

Choosing to stay in a hostel may be a good idea, especially that many of them offer special deals to students who decide to stay for a longer period of time. The biggest disadvantage of living in a hostel is lack of privacy as you would have to share room with other student(s). You may try one of the following hostels:

Hostel Kastoria - located on Egnatia, close to the city centre and the nightlife venues. 

Hostel Arabas - good location, special rates for long-term stays.

Thessaloniki Backpackers - another budget accommodation in Thessaloniki.