Businesses expanding internationally need to decide when and how to file patent applications abroad.
In order to secure patent rights in various countries such as the United States, China, Japan, and Europe, you must file a patent application for each country, but filing for each country individually from the beginning can be burdensome.
The representative system that can be utilized at this time is the PCT international application.
In this article, we will focus on the meaning and procedures of PCT international filing, main periods, cost structure, national phase, and strategies for securing overseas patents.
What is a PCT international application?
PCT stands for Patent Cooperation Treaty.
The PCT international application is a system that allows patent protection to be pursued in multiple PCT contracting countries through a single international application. Applicants can proceed with international stage procedures such as international search and international publication based on one international application and then enter the national stage in the country where they wish to secure actual patent rights.
To summarize, it is as follows:
Domestic patent application → PCT international application → International stage such as international search and international publication → Determination of the country to secure the patent → Enter the national phase in each country → Examination and patent registration by country
The most important part here is that the PCT international application itself does not register the patent right.
In the international stage of the PCT, an international search report and written opinion are prepared, but the final patent registration decision is determined by the patent office of each country entering the national phase in accordance with the laws of that country.
What is the reason for filing a PCT international application?
One of the biggest advantages of PCT international filing is that it allows you time to decide whether and in which country to secure a foreign patent.
For example, let's say there is a company that has applied for a patent for a new technology in Korea. Initially, they considered entering the US and Japan, but the possibility of entering the Chinese or European markets may increase later.
In this way, if the future country of entry is not completely determined at the time of filing a domestic patent application, PCT international application can be used to review patentability at the international stage while examining business plan and marketability.
Through a PCT international application, you can prepare to enter the national phase by approximately 30 months from the priority date, which is the first filing date, in most cases after filing an international application. During this period, you can review the business value of the invention and the possibility of securing a patent.
Therefore, the core advantage of PCT can be seen as “securing time to determine the country and investment scale to secure overseas patents” rather than simply “applying for patents in multiple countries at once.”
When should I file a PCT international application after filing a domestic patent application?
If you first file a patent application domestically and then consider filing overseas, you must check the priority period.
Generally, a method of filing a PCT international application within 12 months from the date of the first patent application and claiming priority based on the original application is used.
For example,
Example: Korean filing on August 12, 2026 → PCT filing claiming that priority by August 12, 2027.
It has the same structure.
To preserve a priority claim, check the applicable filing deadline rather than waiting until twelve months have passed after the first filing.
How does the PCT international application process work?
It is easy to understand the PCT international application by dividing it into the international stage and the national phase.
① PCT international application
First, we proceed with the PCT international application.
Applicants may submit an international application to a Receiving Office that can accept PCT applications, depending on their country or residence. If certain requirements are met, you can also submit it directly to the WIPO International Bureau.
② International search
Following a PCT international filing, an International Searching Authority (ISA) searches for relevant prior art.
As a result, an International Search Report (ISR) is prepared, and a preliminary, non-binding opinion on patentability, including novelty, inventive step, and industrial applicability, is presented through the International Searching Authority's Written Opinion. This data can be used as a reference when deciding which country to enter into the national phase in the future.
However, the results of the international search do not bind the final decision of each country's patent office.
③ International publication
PCT international applications are generally published internationally 18 months after the priority date.
WIPO explains that international applications and international search reports are made public 18 months after the priority date. Published international applications can be checked through PATENTSCOPE.
Therefore, companies preparing for overseas patents must also consider the timing of international publication and the business impact of technology disclosure.
④ Entry into the national phase
After the international stage has progressed, you select the country where you want to secure actual patent rights and enter the national phase.
For example, if you want to secure patent rights in the United States or Japan, you will go through the national phase procedures in those countries. Afterwards, each country's patent office, such as the U.S. Patent Office and the Japanese Patent Office, determines whether or not to register a patent in accordance with the patent laws and examination standards of that country.
In other words, PCT international application = international step to secure overseas patent rights, domestic step = procedure to actually secure patent rights in each country.
Why the PCT international application period of 30 months is important
When preparing for an overseas patent, the expression “PCT 30 months” is often encountered.
The PCT generally allows applicants up to 30 months from the priority date to decide where to enter the national phase, subject to each office’s applicable deadline.
However, the national stage entry deadline may vary depending on the country, so you must check the requirements of the actual entry country.
It is important to use the 30 months of PCT not simply as a “period to postpone patent applications,” but as a decision-making period to design an overseas patent portfolio.
How do PCT international filing costs arise?
Filing a PCT international application does not resolve all foreign patent costs at once.
Typical costs incurred at the international stage include the following:
- Transmittal Fee
- International search fee
- International Filing Fee
The specific amount may vary depending on the receiving office, International Searching Authority, electronic application, number of application pages, etc.
And when you enter the national phase of each country, separate costs are incurred.
For example, for each country, you must consider the national phase official fee + translation fee + local agent fee + subsequent examination and registration costs, etc.
Therefore, the advantages of PCT should not be simply understood as “significantly reducing foreign patent costs.” A more important advantage of the PCT is that it allows time and information to be secured at the international stage before deciding in which country to secure a foreign patent.
PCT international filing is not always necessary for all companies
It is clear that the PCT international application is a useful system, but it is not necessary to use the PCT for all overseas patent applications.
For example, if the country of overseas expansion is already clear and there is a need to quickly file a patent application in that country, it is necessary to compare which method is appropriate between PCT and direct application in each country.
On the other hand, for companies that have not yet decided on overseas expansion countries or are considering marketability in various regions such as the United States, China, Japan, and Europe, a strategy of securing information at the international stage through PCT international filing and then determining the country to enter in the national phase may be useful.
The PCT international application itself is not a system that grants international patent rights.
PCT is a system that allows you to strategically determine the country and timing of securing actual patent rights overseas while carrying out procedures such as international search and international publication based on a single international application.
If you are preparing to expand overseas, please consider the possibility of securing overseas patents from the domestic patent application stage.
This article reflects the information available when it was published. Contact us to discuss your circumstances.