3.2 Start of the European phase processing – the 31-month period under Rule 159(1)

The end of the international phase is defined in Art. 22(1) PCT and Art. 39(1)(a) PCT, which provide that, unless a longer period applies under the national law of the designated/elected Office, the international phase will not end before expiry of 30 months from the filing date or, if priority has been claimed, from the earliest priority date. As laid down in Rule 159(1), the EPO has extended this 30-month time limit by one month in accordance with Art. 22(3) PCT and Art. 39(1)(b) PCT. The international phase in respect of the EPO as designated/elected Office thus ends 31 months after the applicable date, i.e. the filing date or the earliest priority date.

The 31-month period under Rule 159(1) applies irrespective of whether a demand for international preliminary examination was filed. Due to their different legal nature, the individual acts required under Rule 159(1) do not form a unitary procedural step but are legally independent and so not subject to one and the same but rather to independent time limits (A‑XII, 4.2, E‑VIII, 2). This is clear from Rule 159(1) itself, which states that a longer time limit may apply (e.g. Rule 159(1)(f)).

Rules 131, 133 and 134(1), Rule 134(2) and (5) are applicable to the 31-month period for entry into the European phase under Rule 159(1) (E‑VIII, 1.6.2.3).

The date of filing referred to in Rule 159(1) is that accorded under the PCT by the PCT authority which acted as the receiving Office, unless that date is corrected as a result of a review by the EPO as designated/elected Office under, in particular, Art. 24 PCT, Art. 25 PCT or Rule 82ter PCT (A‑II, 4; A‑XII, 3.2; A‑XV, 2 to 4).

For the applicable priority date in cases of errors or omissions in claiming the (earliest) priority, see A‑XV, 4 and 5.

Applicants wishing to obtain a European patent will mostly make full use of the 31-month period and will not take the steps required to enter the European phase until shortly before its expiry. As regards starting the European phase earlier, see A‑XII, 7.1 on making a request for early processing and A‑XV, 2 on cases where European phase processing must start earlier owing to a loss of rights in the international phase.