To answer this question we need to have more details on what kind of work of permit you have, when you received it and under which conditions. No general answer applies.
What requirements does a foreign employee need to meet when working for a certain employer in Greece?
If I obtain a work permit with sponsorship from one Greek employer, can I switch employers and still keep the eligibility of working? Can I change work locations? How long does a work permit last?
It is really hard to issue a working permit. What can be done is to make a branch of o foreign company and be declared as the manager of this branch. Or hire a Greek/European person to be the legal representative.
The necessary requirement that an employee must have to work in the private sector is one of the following types of work permits. There are four types of work permits. Each and every one of them requires some special documents (except the general ‘’easy’’ ones like photos, a copy of your passport legally certified, a deposit in favor of the Greek government, etc.) The first type of work permit is one for dependent work. Firstly, you will need to get a visa of a certain type (not touristic) right after your employer applies for it here in Greece in the competent authority. Also, you will need at least a one-year contract as well as health insurance (private or public). This type of work permit lasts as long as your contract is in force. Second is employees of special “purpose.” These kind of employees are executives of a company, for instance the members of the board of directors, shareholders, general directors, legal representatives, etc. All the special documents that are needed are provided by the firm. The third type is seasonable employment. The fourth type is investment activity. These are the most common work permits in Greece, but I have to say that it is not so easy to get one. Otherwise, in order to work here in Greece, you will need a seven-ear permanent stay (not necessarily legal) and then, after some necessary actions, you can get the type 1 work permit for dependent work. Other requirements are, for instance, zero criminal record, public insurance, VAT number, etc., but taking into account that we are talking about the private sector and not about the public sector, it depends on the employer and it is in his discretion to ask for some extra documents. I am not sure that with someone’s sponsorship one can get a work permit. Assuming this can be possible, then, in my opinion, the employee neither can switch employers and still keep the eligibility of working nor can he change work locations. Regarding the duration of a work permit, again, it depends on many factors like the type of the work permit, the duration of the work contract, etc. Usually, work permits last for one or two years.
According to the Greek Immigration Law, there are four types of work permits issued for foreign citizens and according to each type, some special provisions and terms are applied. The first type of work permit is one for dependent work. Second is employees of special “purpose.” This kind of employees are executives of a company, for instance, the members of the board of directors, shareholders, general directors, legal representatives, etc. The third type is seasonable employment. The fourth type is investment activity(shareholders and executives). In order to answer accurately to your questions is necessary to have more details on what kind of work of permit you are entitled to. If for example the type of the residence permit has been granted for "special purpose" as (a) Executives of Companies established in Greece as subsidiaries of foreigner Companies or (b) an employee of Shipping Companies located in Greece then, in such cases the change of employer is only allowed if the new employer is ranked in the same category as above. The validity of an initial work permit lasts for 2 years. It can be prolonged for another 3 years any time proceeding with prolongation of a valid residence permit.