Applicants must carefully consider the date on which an international application is to be filed and accordingly choose an appropriate way of filing to assure timely receipt at an EPO filing office (see point 47).
The international filing date of an application filed with the EPO as receiving Office is the date on which the application is received at one of the EPO's filing offices or, in exceptional cases (see points 48-51), at a national patent office of an EPC contracting state acting as filing office on behalf of the EPO.
Each international application has a single filing date. The term "international filing date" should therefore not be interpreted as if there is any further filing date in respect of an international application. The word "international" only refers to the fact that the application concerned was filed as an application under the PCT.
The (international) filing date is not to be confused with the date of entry into the European phase before the EPO or into any national phase before a designated/elected Office (see Annex II). This means that even after entry into the European phase any reference to the filing date of the international application concerned is a reference to the international filing date (see points 443444 ff).
Source: http://www.epo.org/applying/international/guide-for-applicants/html/e/ga_b_5.html
Date retrieved: 24 November 2017