What are the key deadlines in Korean patent practice?

Sangwook Je, Partner · Published 26 October 2026

Last verified 9 October 2026

Deadlines at a glance

As of October 2026. Article numbers given alone are those of the Patent Act. [1]

Each deadline in the table has exceptions and requirements. The main ones are set out in the sections below. The deadline in an individual case must be confirmed from the notice and through the agent.

At filing, the deadlines are 1 year for priority and 12 months for the disclosure exception

A priority claim under the Treaty can be made only if the patent application is filed in Korea within 1 year from the filing date of the first application (Patent Act, Art. 54(2)). [1] The priority claim, the name of the country of the first application and the filing date of that application are stated in the written patent application when the patent application is filed (Art. 54(3)). [1]

The priority document or the written statement is submitted within 1 year and 4 months from the earliest priority date (Art. 54(5)). If the document is not submitted within this period, the priority claim loses effect (Art. 54(6)). [1] Within the same 1 year and 4 months, a priority claim can be amended or added (Art. 54(7)). [1] Article 54 does not apply to a PCT international patent application (Art. 199(2)). [1]

The disclosure exception (공지예외) applies where the patent application is filed within 12 months from the date on which the invention was disclosed (Art. 30(1)). [1] Where the application has been laid open, or the registration has been published, in Korea or abroad under a treaty or an Act, this is excluded from disclosure by the person entitled to the patent (Art. 30(1), subparagraph 1, proviso). [1] Where the invention was disclosed by the act of the person entitled to the patent, the disclosure exception claim must be stated in the written patent application. The supporting documents are submitted within 30 days from the filing date of the patent application (Art. 30(2)). [1] On payment of the supplementary fee, the document stating the disclosure exception claim or the supporting documents can also be submitted in the periods in the subparagraphs of Art. 30(3). [1]

Domestic priority based on an earlier Korean application cannot be claimed once 1 year has passed from the filing date of the earlier application (Art. 55(1), subparagraph 1). [1] The earlier application is deemed withdrawn when 1 year and 3 months have passed from its filing date. The cases in the subparagraphs of Art. 56(1) are exceptions. [1]

For details, see “How do I claim priority in Korea, and when must the priority document be filed?”, “What is the grace period under the disclosure exception in Korea?” and “What is domestic priority in Korea, and when is it useful?”. A missed priority period is covered in “Can a missed priority deadline be restored in Korea?”.

The Korean national phase is entered within 2 years and 7 months from the priority date

The applicant of an international patent application must submit the document under Article 203(1) of the Patent Act (the entry document) to the Minister of Intellectual Property within the period for submitting domestic documents (국내서면제출기간). [1] The period for submitting domestic documents is 2 years and 7 months from the priority date under Article 2(xi) of the Patent Cooperation Treaty (Art. 201(1)). [1] An applicant who filed in a foreign language must also submit the Korean translation within the same period (Art. 201(1); Art. 203(1), latter part). [1]

The period for submitting the Korean translation can be extended by 1 month. The request for extension must be stated in the entry document. That entry document must be submitted from 1 month before the expiration date of the period for submitting domestic documents until that expiration date (Art. 201(1), proviso). [1] In this case, the Korean translation can be submitted until the day that is 1 month from the expiration date of the period for submitting domestic documents. [1] This extension does not apply where the Korean translation was already submitted before the entry document. [1]

If the Korean translation of the description of the invention and the claims is not submitted within the period for submitting domestic documents, the international patent application is deemed withdrawn (Art. 201(4)). [1] Where the period for submitting the translation has been extended, the period for submitting domestic documents in Art. 201(3) and the following paragraphs means the extended period. [1] If the entry document is not submitted within the period for submitting domestic documents, the Minister of Intellectual Property issues an order to amend. If the amendment is not made within the designated period (specified period), the international patent application can be invalidated (Art. 203(3) and (4)). [1]

The reference date is the expiration date of the period for submitting domestic documents. Where the period has been extended, it is the expiration date of the extended period. If the applicant files a request for examination within that period, the date of that request is the reference date (Art. 201(5)). [1] An amendment to an international patent application requires all of three conditions. The official fees have been paid, the Korean translation has been submitted, and the reference date has passed (Art. 208(1)). [1] The translation requirement does not apply to an international patent application filed in Korean (same paragraph, subparagraph 2, proviso). [1]

For details, see “What is the deadline for entering the Korean national phase?” and “Can the Korean translation be filed after the national phase deadline?“.

The translation of a patent application in a foreign language is due in 1 year and 2 months, and the request for examination in 3 years

The Korean translation of a patent application in a foreign language is submitted by the day that is 1 year and 2 months from the date under the applicable subparagraph of Article 64(1) of the Patent Act (Art. 42-3(2)). [1] The date under the subparagraphs of Art. 64(1) is the filing date of the application on which the priority claim is based, if there is a priority claim, and the filing date of the patent application if there is none. If there are two or more priority claims, it is the earliest priority date. [1]

The deadline changes if, before that deadline, the applicant receives the notice that a person other than the patent applicant has filed a request for examination (Art. 60(3)). It is then the earlier of the day that is 3 months from the date on which the notice is received and the original deadline (Art. 42-3(2), proviso). [1] If the Korean translation of the specification is not submitted, the application is deemed withdrawn on the day after the deadline (Art. 42-3(4)). [1] The deadline for the amendment stating the claims, where the application was filed without the claims, works in the same way (Art. 42-2(2) and (3)). [1]

Any person can file a request for examination within 3 years from the filing date of the patent application (Art. 59(2)). [1] If no request for examination is filed within this period, the patent application is deemed withdrawn (Art. 59(5)). [1] The 3 years are the period for patent applications filed on or after 1 March 2017. For patent applications filed before that date, the previous 5 years apply (Addenda to Act No. 14035, Art. 19). [1][3]

An international patent application is deemed a patent application filed on the international filing date (Art. 199(1)). [1] The period for the request for examination of a PCT application is therefore counted from the international filing date. Supreme Court Decision 95Nu3336 Decided June 16, 1995 also took the international filing date as the start date. That decision held that the date on which the translation was submitted is not the start date. At the time of the decision, the period for the request for examination was 5 years. [7]

The applicant of an international patent application can file a request for examination only after submitting the Korean translation and paying the official fees (Art. 210, subparagraph 1). The translation requirement does not apply to an international patent application filed in Korean. [1] For an application filed by the legitimate right holder, a divisional application, a separational application or a converted application, a request for examination can be filed within 30 days from the date of that application even after the 3 years have passed (Art. 59(3)). [1]

There is a restoration provision for the case where the period for the request for examination was not observed due to good cause. The request for examination can be filed within 2 months from the date on which the cause ceases to exist. However, it cannot be filed once 1 year has passed from the expiration date of the period (Art. 67-3(1)). [1]

For details, see “Can I file a patent application in English in Korea?” and “When must examination be requested in Korea?“.

The period for submission of a written argument is set by the examiner within 4 months

The deadline for responding to a notice of grounds for rejection is not a period fixed in the Act. It is a period set by the examiner (Patent Act, Art. 63(1)). [1] Article 16(1), subparagraph 2 of the Enforcement Rules of the Patent Act requires the period for submission of a written argument to be set within 4 months. [4] The range of “within 4 months” entered into force on 11 July 2025. The range before that was “within 2 months”. [4] The Addenda to the amended Enforcement Rules that entered into force on 11 July 2025 (Ordinance of the Ministry of Trade, Industry and Energy No. 609) contain only the enforcement date and no applicability provision. [4]

A period set by the examiner can be extended on request (Patent Act, Art. 15(2)). [1] Article 23 of the Regulations for the Handling of Patent and Utility Model Examination Affairs (특허·실용신안 심사사무취급규정) sets the extension in units of 1 month. [6] If the expiration date of the extension requested is not more than 4 months after the expiration date of the designated period, the request for extension of the period is deemed approved when it is received (same Article, paragraph (3)). [6] An extension beyond that range can be approved where the examiner finds it necessary (same Article, paragraph (4)). [6]

After a notice of grounds for rejection has been received, the times at which an amendment can be made are fixed. They are the period for submission of a written argument under that notice of grounds for rejection, and the time when re-examination is requested (Patent Act, Art. 47(1)). [1]

For details, see “How long do I have to respond to a Korean office action? Period for submission of a written argument, extensions and fees“, “What happens if I miss an office action deadline in Korea?” and “When can claims be amended in Korea?“.

The options after a decision of rejection must be taken within 3 months from service of the certified copy

A person who has received a decision of rejection can file a petition for trial within 3 months from the date on which the certified copy of the decision is served (Patent Act, Art. 132-17). [1] The periods for a request for re-examination (재심사) and for a divisional application are also within 3 months from the date on which the certified copy of the decision of rejection is served (Art. 67-2(1); Art. 52(1), subparagraph 2). [1]

The 3 months apply to patent applications for which the certified copy of the decision of rejection is served on or after 20 April 2022 (Addenda to Act No. 18505, Art. 3(1), Art. 7 and Art. 11). [1] Before that, the period for filing a petition for trial was within 30 days from the date on which the certified copy of the decision was served. [3]

The period for filing a petition for trial can be extended only once, by up to 30 days (Art. 15(1)). [1] A person in an area with poor access to transport can obtain one further extension of up to 30 days (Art. 15(1), proviso; Enforcement Rules, Art. 16(4)). [1][4] If the period for filing a petition for trial is extended, the periods for a request for re-examination and for a divisional application become that extended period (Art. 67-2(1); Art. 52(1), subparagraph 2). [1]

The relief provisions for a missed period differ by procedure. Where the period for filing a petition for trial was not observed due to a cause not attributable to the person, subsequent completion of the procedure is possible (Art. 17, subparagraph 1). [1] Where the period for requesting re-examination was not observed due to good cause, re-examination can be requested (Art. 67-3(1), subparagraph 2). [1] Under both provisions, the act must be done within 2 months from the date on which the cause ceases to exist, and it cannot be done once 1 year has passed from the expiration date of the period. [1]

There are three cases in which re-examination cannot be requested. They are where a decision to grant or reject has already been made following re-examination, where a petition for trial under Art. 132-17 has been filed, and where the application is a separational application (Art. 67-2(1), subparagraphs). [1] The case where the decision of rejection has been revoked in the trial (Art. 176(1)) is excluded from the second case. [1] A request for re-examination cannot be withdrawn (Art. 67-2(4)). [1]

If the petition for trial is dismissed, a separational application (분리출원) can be filed within 30 days from the date on which the certified copy of that trial decision is served (Art. 52-2(1)). [1] Where the presiding administrative patent judge has set an additional period under Art. 186(5), it can be filed within that period. [1] The claims that can be stated in the claims of a separational application are limited to those in the subparagraphs of the same paragraph. [1]

For details, see “What is re-examination in Korea, and when should it be requested?”, “How do I appeal a decision of rejection in Korea?“, “When can I file a divisional application in Korea?” and “What is a separational application in Korea?”.

After a decision to grant, the patent fees are paid within 3 months, and then every year

The patent fees for the first three years are paid in one payment within 3 months from the date on which the certified copy of the decision to grant or of the trial decision to register is received (Fee Regulation, Art. 8(5)). [5] After this payment period has passed, late payment is still possible within 6 months (Patent Act, Art. 81(1)). [1] In the period for late payment, 3% to 18% of the patent fee is added, depending on the number of months that have passed (Fee Regulation, Art. 8(6)). [5] If the fee is not paid within the period for late payment either, the patent application is deemed abandoned (Patent Act, Art. 81(3)). [1] Where only part of the patent fee was paid, an order to pay the under-paid patent fee is issued. The period for payment of under-paid patent fees is within 1 month from the date on which the order is received (Art. 81-2(1) and (2)). [1]

A divisional application after a decision to grant can be filed within 3 months from the date on which the certified copy of the decision to grant is served. If the date when the applicant intends to have the grant of the patent registered is less than 3 months away, it can be filed until that date (Art. 52(1), subparagraph 3). [1] Re-examination can be requested from the date on which the certified copy of the decision to grant is served until the grant is registered (Art. 67-2(1)). [1]

The patent fees from year 4 are paid one year at a time, each year in the preceding year, counted from the registration date (Patent Act, Art. 79(1); Fee Regulation, Art. 8(8)). [1][5] The fees for several years or for all years can also be paid together (Patent Act, Art. 79(2)). [1] After the payment period has passed, there is a 6-month period for late payment (Art. 81(1)). [1] In this period for late payment too, 3% to 18% of the patent fee is added, depending on the number of months that have passed (Fee Regulation, Art. 8(8), proviso). [5] If the fee is not paid within the period for late payment either, the patent right is deemed to have been extinguished retroactively. The date from which it is extinguished is the day after the end of the period covered by the patent fees paid (Art. 81(3)). [1]

The current Article 81-3 provides two routes to reinstatement. Where there is good cause, the patent fee can be paid, or the under-paid patent fee can be paid, within 2 months from the date on which the cause ceases to exist. However, this cannot be done once 1 year has passed from the later of the expiration date of the period for late payment and the expiration date of the period for payment of under-paid patent fees (paragraph (1)). [1] The patentee of an extinguished patent right can pay twice the patent fee and apply for reinstatement within 3 months from the expiration date of the period for late payment or of the period for payment of under-paid patent fees (paragraph (3)). [1]

Article 81-3 changes on 16 March 2027. The amended Article provides that, where the failure was not intentional, reinstatement is applied for within 1 year from the later expiration date, on payment of an amount set by Prime Ministerial Decree. The current paragraph (3) is deleted. [2] The amended provision applies to cases in which the period for late payment or the period for payment of under-paid patent fees expires on or after 16 March 2027 (Addenda to Act No. 21955, Art. 2). [2] The other Articles cited in this article are not changed by the amended Patent Act. [1][2]

For details, see “What is the deadline to pay the registration fee in Korea?“, “What can still be done after a decision to grant in Korea?”, “How much are Korean patent annual fees, and when are they due?“, “What happens if a Korean patent annual fee is paid late?”, “Can a lapsed Korean patent be reinstated?” and “What changes in the Korean Patent Act on 16 March 2027?”.

After registration, the deadlines are 6 months for a request for revocation, 30 days for a revocation action and 3 months for an extension application

Any person can file a request for revocation of a granted patent (특허취소신청). The period runs from the registration date of the patent right until the day that is 6 months after the date of publication of registration (Patent Act, Art. 132-2(1)). [1] The request for revocation of a granted patent applies to patent rights registered on or after 1 March 2017 (Addenda to Act No. 14035, Art. 10). [1][3]

A revocation action must be filed within 30 days from the date on which the certified copy of the trial decision is served (Art. 186(3)). [1] These 30 days are an invariable period (Art. 186(4)). [1] The presiding administrative patent judge can set an additional period ex officio for a person in a remote area or an area with poor access to transport (Art. 186(5)). The additional period is within 30 days (Enforcement Rules, Art. 16(5)). [1][4]

The term of the patent runs from the registration date until the day that is 20 years after the filing date of the patent application (Art. 88(1)). [1]

An application for registration of an extension of a patent also has deadlines. For patent term extension for approval, etc., the application must be filed within 3 months from the date on which the approval, etc. was obtained. It cannot be filed from 6 months before the expiration of the term of the patent (Art. 90(2)). [1] For patent term extension for delay in registration, the application must be filed within 3 months from the registration date of the patent right (Art. 92-3(2)). [1]

For details, see “What is a request for revocation of a granted patent in Korea, and what is its deadline?”, “How are trial decisions appealed to the Intellectual Property High Court of Korea (Patent Court of Korea)?”, “How long does a Korean patent last?“, “How does patent term extension work in Korea?” and “How does patent term extension for delay in registration work in Korea?”.

Example: deadlines counted by date

Periods are calculated under Article 14 of the Patent Act. The first day of a period is not counted (subparagraph 1). [1] A period set in months or years ends on the day before the day, in the last month or year, that corresponds to the start date (subparagraph 3). [1] If the last day of a period is an official holiday, the period expires on the following day. Saturdays and Workers’ Day are included in these official holidays (subparagraph 4). [1] Article 2 of the Regulations on Public Holidays of Government Offices (관공서의 공휴일에 관한 규정) makes Sundays public holidays of government offices. [8]

The schedule below assumes a PCT application with a priority date of 12 March 2025 and an international filing date of 12 March 2026. The certified copy of the decision of rejection is assumed to be served on 3 September 2029. The four expiration dates in the table are not Saturdays or Sundays. They are also not public holidays that the same Regulations fix by date, or substitute public holidays for them. [8] Public holidays fixed by the lunar calendar and days that the government designates from time to time were not taken into account.

FAQ

Is the deadline for entering the Korean national phase of a PCT application 30 months?

No. The period for submitting domestic documents in Korea is 2 years and 7 months from the priority date (Patent Act, Art. 201(1)). [1] If an extension is requested, the Korean translation can be submitted until the day that is 1 month from the expiration date of that period. [1]

Is the deadline for responding to a Korean Notice of Preliminary Rejection 2 months?

The range under the current rule is within 4 months (Enforcement Rules, Art. 16(1), subparagraph 2). [4] “Within 2 months” was the range before 11 July 2025. [4] The actual deadline is the period for submission of a written argument stated in the notice.

Can an application be revived after the deadline for the request for examination is missed?

If no request for examination is filed within the period for the request for examination, the patent application is deemed withdrawn (Patent Act, Art. 59(5)). [1] There is a restoration provision for the case where the period was not observed due to good cause. The request for examination can be filed within 2 months from the date on which the cause ceases to exist. However, it cannot be filed once 1 year has passed from the expiration date of the period (Art. 67-3(1)). [1] The same provision also applies to the period for requesting re-examination. [1]

What happens if the last day of a deadline is a Saturday?

In a patent-related procedure, if the last day of a period is an official holiday, the period expires on the following day. Saturdays and Workers’ Day are included in these official holidays (Patent Act, Art. 14, subparagraph 4). [1]

How DEFINE IP Law Firm handles this

At DEFINE IP Law Firm, we manage the deadlines of each case by separating periods fixed by statute from periods set by the examiner. We confirm each deadline from the date of service of the notice and the calculation rules of Article 14 of the Patent Act. We tell the applicant which deadlines can be extended and which cannot. For questions about Korean patent deadlines, please write to contact@defineip.kr.

Sources

1. Patent Act (특허법) (Act No. 21134), in force from 11 November 2025. Art. 14, Art. 15, Art. 17, Art. 30, Art. 42-2, Art. 42-3, Art. 47, Art. 52, Art. 52-2, Art. 54, Art. 55, Art. 56, Art. 59, Art. 60, Art. 63, Art. 64, Art. 67-2, Art. 67-3, Art. 79, Art. 81, Art. 81-2, Art. 81-3, Art. 88, Art. 89, Art. 90, Art. 92-2, Art. 92-3, Art. 132-2, Art. 132-17, Art. 176, Art. 186, Art. 199, Art. 201, Art. 203, Art. 208, Art. 210, Addenda (Act No. 14035, Art. 10 and Art. 19; Act No. 18505, Art. 3, Art. 7 and Art. 11). https://www.law.go.kr/법령/특허법 (verified 9 October 2026)
2. Patent Act (특허법) (Act No. 21955), promulgated on 15 September 2026, scheduled to enter into force on 16 March 2027. Art. 81-3, Addenda, Art. 1 and Art. 2. https://www.law.go.kr/법령/특허법 (verified 9 October 2026)
3. Earlier versions of the Patent Act (특허법). Act No. 13096 (in force from 29 July 2015), Art. 59(2); Act No. 18409 (in force from 18 February 2022), Art. 132-17; the enforcement dates of Act No. 14035 (1 March 2017) and of Act No. 18505 (20 April 2022). https://www.law.go.kr/법령/특허법 (verified 9 October 2026)
4. Enforcement Rules of the Patent Act (특허법 시행규칙) (Prime Ministerial Decree No. 2115), in force from 14 May 2026. Art. 16(1), (4) and (5). Earlier versions: Ordinance of the Ministry of Trade, Industry and Energy No. 609 (in force from 11 July 2025) and its Addenda, and Art. 16(1) of Ordinance of the Ministry of Trade, Industry and Energy No. 579 (in force from 1 November 2024). https://www.law.go.kr/법령/특허법시행규칙 (verified 9 October 2026)
5. Regulation on the Collection of Patent Fees, etc. (특허료 등의 징수규칙) (Prime Ministerial Decree No. 2098), in force from 27 February 2026. Art. 8(5), (6) and (8). https://www.law.go.kr/법령/특허료등의징수규칙 (verified 9 October 2026)
6. Regulations for the Handling of Patent and Utility Model Examination Affairs (특허·실용신안 심사사무취급규정) (MOIP Directive No. 41), in force from 1 July 2026. Art. 23. https://www.law.go.kr/행정규칙/특허·실용신안심사사무취급규정 (verified 9 October 2026)
7. Supreme Court of Korea (대법원), Supreme Court Decision 95Nu3336 Decided June 16, 1995 (95누3336). https://www.law.go.kr/판례/(95누3336) (verified 9 October 2026)
8. Regulations on Public Holidays of Government Offices (관공서의 공휴일에 관한 규정) (Presidential Decree No. 36290), in force from 11 May 2026. Art. 2 and Art. 3. https://www.law.go.kr/법령/관공서의공휴일에관한규정 (verified 9 October 2026)