According to European Patent Convention (EPC) Regulations,

To pursue the international application before the EPO as designated or elected Office, the applicant must as one of the procedural steps within 31 months from the date of filing, or, if for the international application priority has been claimed, from the earliest priority date,

pay the renewal fee for the third year ( actually in amount of 690,- EUR) if it has fallen due before expiry of the 31-month period;

 

A renewal fee for third year for the European patent application in respect of the coming year shall be due on the last day of the month containing the second anniversary of the date of filing of that patent application. Accordingly if from filing the International (PCT) Application or, if with that patent application priority has been claimed, from the earliest priority date, before the deadline for entry into European phase (31 months) have passed from the last day of the month containing the second anniversary of the date of filing of that patent application or from its claimed priority date, than the Renewal fee for third year is to be paid at the entry of that International (PCT) Application into European phase.

The amount of the Renewal fee is given according to the actually valid EPO Schedule of fees and charges which are regularly updated each year.