LINE Ads Starter Guide: Setup, Budgeting, and Targeting
LINE Ads Starter Guide: Setup, Budgeting, and Targeting
Nov 19, 2025
Over 90 million monthly active users. LINE is a gigantic platform in Japanese marketing that cannot be ignored. LINE ads, which allow businesses to directly approach this massive user base, can become a powerful weapon for business growth.
However, behind its power lurk numerous pitfalls that beginners may easily stumble upon. Without knowing the correct "How to Start LINE Ads," you risk wasting considerable time and budget on campaigns that might get denied before even generating a single impression due to overlooked technical requirements or a strict screening process.
This article is a complete guide for beginners in LINE advertising. It uncovers seven unexpected pitfalls that everyone faces when starting advertising, but no one tells you about, and provides clear and actionable solutions for each.
1. Pitfall 1: The Invisible Premise That You Must Have a "LINE Official Account" Before Creating an "Ad Account"
Many beginners get confused initially by the fact that they cannot create an ad account directly. To start LINE ads, you must first have a "LINE Official Account" managed by the advertiser themselves.
This is at the core of LINE's advertiser authentication process. When creating an ad account, linking it to an existing LINE Official Account is a mandatory requirement, and the display name and profile picture of that official account will be used as proof of the advertiser's identity.
Pro Tip: One of the most common reasons for denial in ad account review is the mismatch between the advertiser information registered in the ad account and the details of the linked LINE Official Account (especially the "display name" and "profile picture"). Be sure to check that both sets of information match perfectly before applying.
2. Pitfall 2: The Review Is Not Just Once! Two-Step Review Process of "Account" and "Ads"
The review process for LINE ads is divided into two stages, and failing to understand this may lead to unexpected schedule delays. Many advertisers anticipate only the review of creatives, but there is an initial review of the business itself that occurs first.
Ad Account Review: This review is for the advertiser as a "business". It starts after the ad account is created and the necessary information is entered, usually taking 3 to 5 business days. Certain industries defined by LINE's guidelines, such as adult content, some gambling, and specific religious organizations, will not be approved at this stage.
Ad Review: After the account is approved, this review pertains to individual ads (creatives, text, landing pages) being submitted. This can sometimes be completed in as little as 5 minutes but may take up to 5 business days depending on the content.
The two-step process can become a pitfall if one does not anticipate waiting several days for the initial "Ad Account Review" even if a perfect ad creative is prepared. It is essential to approach the account opening with a schedule that allows for ample time, working backward from the campaign launch date. The "Ad Account Review" verifies the legitimacy of the business, while the "Ad Review" mainly checks the "three-way consistency" explained in the next section.
3. Pitfall 3: The Biggest Reason for Review Denials. The Iron Rule of "Three-Way Consistency"
The most important rule for passing the review of LINE ads is "three-way consistency." This principle requires that all information related to the ad must perfectly match without any discrepancies, and the lack of this consistency is the primary cause of review denials.
This principle of consistency begins before creating the ad, namely with linking to the LINE Official Account. The display name and profile picture of the linked official account must perfectly match the advertiser information that will be registered and the content of the ads or landing pages being delivered—this is a prerequisite for passing the review.
Registered Information of the Ad Account
The official name of the advertiser, business category, official website URL, etc.—information that proves the advertiser's identity. This serves as the baseline for all information.
Ad Creatives and Text
The images or videos being delivered, along with the title and description, must correspond to the business details registered in the ad account.
Content of the Landing Page (LP)
On the page that users arrive at after clicking the ad, the products or services presented in the ad must be clearly displayed, and it must be explicitly noted that it is operated by the advertiser registered in the ad account. Broken links and incomplete pages are also subject to immediate denial.
Example of Failure: If an ad account registered as "ABC Cosmetics" runs an ad for health supplements and links to the LP of "XYZ Health Foods," this three-way consistency is broken, resulting in immediate denial.
4. Pitfall 4: The Trap of Measurement Tags. Failing to Install in the Correct Order Prevents Optimization from Functioning
To maximize the results of LINE ads, it is essential to accurately measure conversions (purchases, sign-ups, etc.) and enable optimization through AI. Necessary for this is the installation of measurement tags called "LINE Tag."
There are mainly three types of LINE Tags.
Base Code: The foundational code for measurement, which must be installed within the
<head>section of all pages to be measured.Conversion Code: Tags installed on result pages, such as purchase completion pages.
Custom Event Code: Tags that measure specific actions (e.g., adding to cart).
The technical pitfall here is that the conversion code and custom event code must be installed immediately after the base code within the HTML source code, according to strict rules.
If this order is incorrect, the measurement may produce a "silent error," preventing it from functioning without visible error displays. As a result, conversions won't be measured, and the AI optimization algorithm will learn from incorrect data (or zero data), leading to the waste of advertising costs while continuing to deliver ineffective ads.
Pro Tip: To prevent such technical mistakes, it is strongly recommended to use Google Tag Manager (GTM). With GTM, you can manage tag installations and the correct firing order easily and reliably without directly editing the website's code.
5. Pitfall 5: Strict Constraints on Creatives. The Unknown "20% Rule" and Resolution Limits
LINE ads have unique and strict constraints that do not exist in other media. Proceeding with production without knowing these can lead directly to review denials or reduced distribution performance.
Strict Character Limits: The main text elements of the ad must be kept very concise. The title (text) is limited to 20 characters, and the description is limited to 75 characters. Concise and powerful messaging is required.
The Unwritten 20% Text Rule: This is not explicitly stated in the official guidelines but is an important rule known through the experience of many advertising agencies. If the area of text within an image exceeds 20%, the distribution amount of the ad tends to be suppressed. Keep text on images to a minimum.
Videos Are Downscaled to 720p: Even if you upload high-quality videos at 1080p, the maximum resolution during distribution to users is capped at 720p. It is crucial to check during production whether text and details are still visible without being distorted at 720p.
Format Optimization: To maximize distribution opportunities, start with the two most versatile formats: Card (1200x628px) and Square (1080x1080px). Most importantly, understand that gaining delivery qualifications for the "Talk List," the most viewed ad section within LINE, is not optional but a crucial condition for maximizing reach. The delivery of creatives in Image (small) (600x400px) format is no longer a choice but a strategically necessary task.
6. Pitfall 6: Avoiding User Discomfort. Subjective Expressions That Are Disliked During Reviews
LINE places great importance on user experience across its platform, establishing strict standards not only for technical specifications but also for content in advertising expressions. Ads that could cause discomfort to users are quickly denied.
Particularly avoidable expressions include the following:
Stoking Insecurities: Expressions that overly magnify "skin troubles" or exaggerated "before and after" images depicting physical changes that stimulate users' insecurities are prohibited.
Misuse of Superlatives: When using superlative expressions like "best" or "No. 1," clear evidence from credible third-party surveys must be noted within the advertisement or on the landing page, so it is readily available. Unsubstantiated superlative expressions will not be accepted.
Mimicking the LINE UI: Using LINE's brand color green excessively or designing ads that resemble LINE’s icons or message notifications to make it appear as though they are LINE's official features or messages is strictly prohibited.
7. Pitfall 7: Discovering the "Winning Pattern." A/B Testing Is Mandatory, Not Optional
Even if you overcome all the previous pitfalls and successfully start ad distribution, that is not the end. The real battle begins here. Even with perfect settings, success is not guaranteed. You must actively discover the "winning pattern" for your products or services.
The only way to do this is through A/B testing. Create multiple variations of ads that change only one element at a time—testing multiple image patterns with the same text or multiple texts with the same image—and distribute them simultaneously.
No matter how outstanding an ad may be, displaying the same ad repeatedly to the same user can lead to "ad fatigue," diminishing its effectiveness and shortening its lifespan. Rather than viewing A/B testing as a one-time project to find a winner, treat it as a "continuous operational process" to secure ongoing results, which will be key to maintaining success.
If you use the tool called "LINE Creative Lab", which LINE offers for free, you can easily create static or animated ad creatives based on templates. Utilize this to accelerate the testing cycle.
Conclusion
The key to success in LINE advertising lies more in meticulous preparation than in the size of the advertising budget. Deeply understanding the strict review processes, accurate technical setups, and unique creative guidelines, and taking preemptive measures will help you avoid the unnecessary frustrations many beginners experience and unlock the true potential the platform has to offer.
Once the campaign begins to run smoothly, the next challenge is "optimization." Cascade is an AI-powered marketing and ad optimization platform designed to maximize the effectiveness of advertising spend for each yen invested. If you are ready to elevate your results to the next level, explore what Cascade has to offer.
Over 90 million monthly active users. LINE is a gigantic platform in Japanese marketing that cannot be ignored. LINE ads, which allow businesses to directly approach this massive user base, can become a powerful weapon for business growth.
However, behind its power lurk numerous pitfalls that beginners may easily stumble upon. Without knowing the correct "How to Start LINE Ads," you risk wasting considerable time and budget on campaigns that might get denied before even generating a single impression due to overlooked technical requirements or a strict screening process.
This article is a complete guide for beginners in LINE advertising. It uncovers seven unexpected pitfalls that everyone faces when starting advertising, but no one tells you about, and provides clear and actionable solutions for each.
1. Pitfall 1: The Invisible Premise That You Must Have a "LINE Official Account" Before Creating an "Ad Account"
Many beginners get confused initially by the fact that they cannot create an ad account directly. To start LINE ads, you must first have a "LINE Official Account" managed by the advertiser themselves.
This is at the core of LINE's advertiser authentication process. When creating an ad account, linking it to an existing LINE Official Account is a mandatory requirement, and the display name and profile picture of that official account will be used as proof of the advertiser's identity.
Pro Tip: One of the most common reasons for denial in ad account review is the mismatch between the advertiser information registered in the ad account and the details of the linked LINE Official Account (especially the "display name" and "profile picture"). Be sure to check that both sets of information match perfectly before applying.
2. Pitfall 2: The Review Is Not Just Once! Two-Step Review Process of "Account" and "Ads"
The review process for LINE ads is divided into two stages, and failing to understand this may lead to unexpected schedule delays. Many advertisers anticipate only the review of creatives, but there is an initial review of the business itself that occurs first.
Ad Account Review: This review is for the advertiser as a "business". It starts after the ad account is created and the necessary information is entered, usually taking 3 to 5 business days. Certain industries defined by LINE's guidelines, such as adult content, some gambling, and specific religious organizations, will not be approved at this stage.
Ad Review: After the account is approved, this review pertains to individual ads (creatives, text, landing pages) being submitted. This can sometimes be completed in as little as 5 minutes but may take up to 5 business days depending on the content.
The two-step process can become a pitfall if one does not anticipate waiting several days for the initial "Ad Account Review" even if a perfect ad creative is prepared. It is essential to approach the account opening with a schedule that allows for ample time, working backward from the campaign launch date. The "Ad Account Review" verifies the legitimacy of the business, while the "Ad Review" mainly checks the "three-way consistency" explained in the next section.
3. Pitfall 3: The Biggest Reason for Review Denials. The Iron Rule of "Three-Way Consistency"
The most important rule for passing the review of LINE ads is "three-way consistency." This principle requires that all information related to the ad must perfectly match without any discrepancies, and the lack of this consistency is the primary cause of review denials.
This principle of consistency begins before creating the ad, namely with linking to the LINE Official Account. The display name and profile picture of the linked official account must perfectly match the advertiser information that will be registered and the content of the ads or landing pages being delivered—this is a prerequisite for passing the review.
Registered Information of the Ad Account
The official name of the advertiser, business category, official website URL, etc.—information that proves the advertiser's identity. This serves as the baseline for all information.
Ad Creatives and Text
The images or videos being delivered, along with the title and description, must correspond to the business details registered in the ad account.
Content of the Landing Page (LP)
On the page that users arrive at after clicking the ad, the products or services presented in the ad must be clearly displayed, and it must be explicitly noted that it is operated by the advertiser registered in the ad account. Broken links and incomplete pages are also subject to immediate denial.
Example of Failure: If an ad account registered as "ABC Cosmetics" runs an ad for health supplements and links to the LP of "XYZ Health Foods," this three-way consistency is broken, resulting in immediate denial.
4. Pitfall 4: The Trap of Measurement Tags. Failing to Install in the Correct Order Prevents Optimization from Functioning
To maximize the results of LINE ads, it is essential to accurately measure conversions (purchases, sign-ups, etc.) and enable optimization through AI. Necessary for this is the installation of measurement tags called "LINE Tag."
There are mainly three types of LINE Tags.
Base Code: The foundational code for measurement, which must be installed within the
<head>section of all pages to be measured.Conversion Code: Tags installed on result pages, such as purchase completion pages.
Custom Event Code: Tags that measure specific actions (e.g., adding to cart).
The technical pitfall here is that the conversion code and custom event code must be installed immediately after the base code within the HTML source code, according to strict rules.
If this order is incorrect, the measurement may produce a "silent error," preventing it from functioning without visible error displays. As a result, conversions won't be measured, and the AI optimization algorithm will learn from incorrect data (or zero data), leading to the waste of advertising costs while continuing to deliver ineffective ads.
Pro Tip: To prevent such technical mistakes, it is strongly recommended to use Google Tag Manager (GTM). With GTM, you can manage tag installations and the correct firing order easily and reliably without directly editing the website's code.
5. Pitfall 5: Strict Constraints on Creatives. The Unknown "20% Rule" and Resolution Limits
LINE ads have unique and strict constraints that do not exist in other media. Proceeding with production without knowing these can lead directly to review denials or reduced distribution performance.
Strict Character Limits: The main text elements of the ad must be kept very concise. The title (text) is limited to 20 characters, and the description is limited to 75 characters. Concise and powerful messaging is required.
The Unwritten 20% Text Rule: This is not explicitly stated in the official guidelines but is an important rule known through the experience of many advertising agencies. If the area of text within an image exceeds 20%, the distribution amount of the ad tends to be suppressed. Keep text on images to a minimum.
Videos Are Downscaled to 720p: Even if you upload high-quality videos at 1080p, the maximum resolution during distribution to users is capped at 720p. It is crucial to check during production whether text and details are still visible without being distorted at 720p.
Format Optimization: To maximize distribution opportunities, start with the two most versatile formats: Card (1200x628px) and Square (1080x1080px). Most importantly, understand that gaining delivery qualifications for the "Talk List," the most viewed ad section within LINE, is not optional but a crucial condition for maximizing reach. The delivery of creatives in Image (small) (600x400px) format is no longer a choice but a strategically necessary task.
6. Pitfall 6: Avoiding User Discomfort. Subjective Expressions That Are Disliked During Reviews
LINE places great importance on user experience across its platform, establishing strict standards not only for technical specifications but also for content in advertising expressions. Ads that could cause discomfort to users are quickly denied.
Particularly avoidable expressions include the following:
Stoking Insecurities: Expressions that overly magnify "skin troubles" or exaggerated "before and after" images depicting physical changes that stimulate users' insecurities are prohibited.
Misuse of Superlatives: When using superlative expressions like "best" or "No. 1," clear evidence from credible third-party surveys must be noted within the advertisement or on the landing page, so it is readily available. Unsubstantiated superlative expressions will not be accepted.
Mimicking the LINE UI: Using LINE's brand color green excessively or designing ads that resemble LINE’s icons or message notifications to make it appear as though they are LINE's official features or messages is strictly prohibited.
7. Pitfall 7: Discovering the "Winning Pattern." A/B Testing Is Mandatory, Not Optional
Even if you overcome all the previous pitfalls and successfully start ad distribution, that is not the end. The real battle begins here. Even with perfect settings, success is not guaranteed. You must actively discover the "winning pattern" for your products or services.
The only way to do this is through A/B testing. Create multiple variations of ads that change only one element at a time—testing multiple image patterns with the same text or multiple texts with the same image—and distribute them simultaneously.
No matter how outstanding an ad may be, displaying the same ad repeatedly to the same user can lead to "ad fatigue," diminishing its effectiveness and shortening its lifespan. Rather than viewing A/B testing as a one-time project to find a winner, treat it as a "continuous operational process" to secure ongoing results, which will be key to maintaining success.
If you use the tool called "LINE Creative Lab", which LINE offers for free, you can easily create static or animated ad creatives based on templates. Utilize this to accelerate the testing cycle.
Conclusion
The key to success in LINE advertising lies more in meticulous preparation than in the size of the advertising budget. Deeply understanding the strict review processes, accurate technical setups, and unique creative guidelines, and taking preemptive measures will help you avoid the unnecessary frustrations many beginners experience and unlock the true potential the platform has to offer.
Once the campaign begins to run smoothly, the next challenge is "optimization." Cascade is an AI-powered marketing and ad optimization platform designed to maximize the effectiveness of advertising spend for each yen invested. If you are ready to elevate your results to the next level, explore what Cascade has to offer.
＼FreeDownload Now／
＼FreeDownload Now／
＼FreeDownload Now／
Table of Contents
© 2025 Cascade Inc, All Rights Reserved.
© 2025 Cascade Inc, All Rights Reserved.
© 2025 Cascade Inc, All Rights Reserved.
© 2025 Cascade Inc, All Rights Reserved.