I have a US non-provisional that claims priority to a provisional one. It is not published yet but its priority period has expired. I also have a pending Australian provisional application for exactly the same invention. Can I file a PCT application claiming the priority date only of the Australian provisional which is the first application in this country but has a later filing date than the US one?

  • Does the australian one claim any priority?
    – user18033
    Commented May 24, 2018 at 14:01
  • No, it is a provisional one and it is independent, without claiming priority to the US one.
    – Piterz
    Commented May 24, 2018 at 14:13
  • Is any of those published? Can you give us the dates? Commented May 25, 2018 at 5:50
  • None of them have been published yet. The invention is not published either. The dates are: US Provisional (02 April 2017); US Non-provisional, claiming priority to it (01 April 2018); Australian Provisional, without claiming any priority (29 April 2018)
    – Piterz
    Commented May 25, 2018 at 8:28

2 Answers 2


No. Under the Paris Convention you can only claim priority to the first filed application. The exception to this is if the first application is abandoned without being published and was never used in a priority claim, then the second application in that same country can be used for priority. Article 4 is very clear.

Article 4 C (4) A subsequent application concerning the same subject as a previous first application within the meaning of paragraph (2), above, filed in the same country of the Union. shall be considered as the first application, of which the filing date shall be the starting point of the period of priority, if, at the time of filing the subsequent application, the said previous application has been withdrawn, abandoned, or refused, without having been laid open to public inspection and without leaving any rights outstanding, and if it has not yet served as a basis for claiming a right of priority. The previous application may not thereafter serve as a basis for claiming a right of priority.


If I may summarize the timeline:
02 April 2017 - US Provisional(Not published)
01 April 2018 - US Non-Provisional, converted from US Provisional (Not published)
29 April 2018 - Australian Provisional (Not published)
24 May 2018 - Day you asked the question

Can you file a PCT claiming the priority date of the Australian Provisional?
If you have not made any public disclosure, the answer is yes.

The applicable rule here:

Article 4.C(4) of the Paris Convention dictates that the 12-month window for filing a PCT application commences on the filing date of the earliest application in the family.

In other words, you cannot file a PCT application based on the priority of your US Provisional because the 12-month window has passed.

However, you can still file a PCT application based on the priority of your Australian Provisional since you are still within the 12-month window.

Note that you will need to withdraw your US Non-Provisional to prevent the novelty of your subject matter in your PCT Application from being negated by the US Non-Provisional when it publishes.

This link provides more information: https://www.smithhopen.com/PCT_filing_deadlines_and_priority_dates.aspx

  • 1
    I can't find a PCT reference, but I think the PCT is in line with the epc on this (epo.org/law-practice/legal-texts/html/guidelines/e/…). The australian prov. was not the first application. It is not considered the first app. because the US non prov. and the us prov. had rights outstanding/were used for priority. Therefore the australian prov. would not be a valid priority application. Am I missing something or is the PCT rule different?
    – user18033
    Commented Jul 7, 2018 at 18:17
  • 1
    but “the same invention“ relates to the subject matter independently of claiming priority. Example for ep: ep1 later ep2 later ep1 abandoned later ep3 claiming priority of ep2 all with identical content => priority not valid.
    – user18033
    Commented Jul 8, 2018 at 6:44
  • 1
    I'm not sure what happens if the applications are from different countries. But the us prov. has been used for claiming priority and should impede claiming priority even if the non. Prov is abandoned
    – user18033
    Commented Jul 8, 2018 at 7:00
  • 1
    @Piterz not prior art, but the epo requires you to claim priority from the youngest application for the same subject matter that still has rights outstanding. In my opinion the epo would therefore not recognize the priority of the pct from the aus because the us has the same subject matter (same invention).
    – user18033
    Commented Aug 7, 2018 at 7:15
  • 1
    @Piterz maybe they define as family all applications relating, whether they draw priority or not. Imho you can file independently as many applications as you want, but maybe there is a PCT provision impeding this.
    – user18033
    Commented Aug 10, 2018 at 9:50

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