Email or LINE? We tested both for businesses in Japan. Here’s what actually drives growth and what wastes budget.
When I first started working as a digital marketing agency in Japan, this was the question I heard more than any other.
"should I be doing LINE or email marketing?"
And honestly, I didn't have a simple answer at first.
I tested both.
I made mistakes with both.
I watched clients waste money on the wrong one — and I watched others absolutely crush it when they finally got the strategy right.
So let me save you the trial and error.
I'm Aman from Boostify Japan — a bilingual marketing agency in Tokyo helping startups, small businesses, and foreign businesses in Japan grow online.
Here’s everything I learned from working with restaurants, gyms, clinics, ecommerce brands, and foreign startups trying to grow in Japan.
Before I get into the comparison, I want to be honest about something most marketing blogs skip over.
Japan is not like the US, the UK, or Europe.
Japanese consumers don’t just buy from brands — they build long-term relationships with them. Trust, consistency, and personal connection matter more here than aggressive promotions or flashy campaigns.
I learned this the hard way when I first started helping foreign businesses in Japan enter the Japanese market.
What worked back home simply didn’t work here.
The entire approach needed to change.
That’s why when I talk about email marketing in Japan and LINE marketing in Japan, I’m not just comparing two tools.
I’m comparing two completely different ways of connecting with Japanese consumers and growing a business in Japan.
LINE has over 99 million monthly active users in Japan.
That’s roughly 80% of the entire population using one single app every single day.
When I first saw those numbers, I honestly thought:
"Okay, this is a no-brainer."
Every business doing digital marketing in Japan should probably be using LINE.
And for some businesses, I was absolutely right.
I worked with a ramen restaurant in Shibuya that was struggling to fill tables on weekday evenings.
We set up a LINE Official Account, grew their follower list to over 3,000 people, and started sending weekend coupons every Thursday night.
The results were insane.
The owner genuinely couldn’t believe it.
That’s the power of LINE marketing in Japan.
Messages land directly in the same chat feed as your customers’ friends and family. It feels personal, immediate, and natural.
And Japanese consumers actually open it.
But then I started noticing the problems nobody talks about.
The costs kept increasing as audiences grew.
Automation was limited.
And when some of my foreign business clients wanted to reach international customers too, LINE simply didn’t work.
Most importantly:
The audience didn’t belong to the client.
It belonged to LINE.
When I first started recommending email marketing to businesses in Japan, some clients honestly looked at me like I was crazy.
"Email? Isn’t that outdated?"
But the actual data told a completely different story.
The average email open rate in Japan is around 31.75% — significantly higher than many global markets.
And once I started testing it properly, I understood why.
I worked with a Tokyo fitness startup that kept losing customers after the first month.
They had:
New members would join, get excited, then quietly disappear.
So we built a simple automated email sequence.
Nothing complicated.
Just:
That one system dramatically improved retention without increasing ad spend.
That’s when I realized something important.
Good email marketing in Japan isn’t about sending newsletters.
It’s about building long-term relationships automatically.
And unlike social platforms, your email list becomes more valuable every single month.
FactorLINE MarketingEmail MarketingOpen Rate60–70%31.75%Audience OwnershipPlatform-owned audienceFully owned customer listAutomationLimitedAdvancedCost at ScaleIncreases with volumeStays affordableBest ForPromotions, couponsNurturing, retentionReaches International ClientsJapan-focusedGlobal reachLong-term AssetShort-term engagementLong-term business assetB2B EffectivenessModerateStrongBilingual SupportPrimarily JapaneseEnglish + Japanese
From what I’ve personally seen working in Tokyo digital marketing, LINE works best for:
If your business depends heavily on foot traffic and local engagement, LINE can be incredibly powerful.
Especially in Japan.
Email marketing becomes the stronger option for:
If you want a long-term marketing asset that grows over time, email marketing is usually the smarter foundation.
Even though Boostify Japan is still a growing agency, we've already worked closely with startups, local businesses, and foreign-owned companies trying to grow in Japan through digital marketing.
And after testing both email marketing and LINE marketing across different types of businesses, here’s the honest answer I now give clients:
Don’t rely on only one.
But if you have to start somewhere, start with email marketing.
Here’s why.
LINE followers belong to the platform.
Your email list belongs to your business.
That matters long term.
Good email automation saves time while increasing customer retention.
Once properly built, it keeps working in the background every single day.
As a bilingual marketing agency in Japan, many businesses we work with target both Japanese and international customers.
Email works globally.
LINE does not.
Japanese consumers value consistency, trust, and long-term relationships.
Email marketing helps businesses stay connected with customers without feeling overly aggressive.
That relationship-building matters enormously in Japan.
Paid ads stop working the moment you stop spending.
A strong email list continues generating value month after month.
That’s one reason email marketing remains one of the highest ROI digital marketing channels in Japan.
Many businesses focus heavily on LINE because the engagement numbers look exciting.
And honestly, the engagement is impressive.
But many companies forget to build:
That’s where email marketing becomes incredibly powerful.
The smartest approach is usually:
That combination works extremely well in the Japanese market.
At Boostify Japan, we help startups, foreign businesses, and local companies build high-converting digital marketing systems in Japan.
Including:
Whether you’re launching a startup in Tokyo or scaling an existing business across Japan, we help businesses build marketing systems designed for long-term growth.
Book your free consultation with Boostify Japan today.
