"If I block him, will he know?" "If I check whether he's blocked me, will he find out?" — these are two different questions that get tangled together. This post answers both.
Direct answer: LINE doesn't notify them
No. LINE's official Help Center states it explicitly:
Even if you hide, block, or delete someone, they will not be notified.
At the moment of the block:
- No push notification appears on their phone.
- The chat thread on their side doesn't disappear and gets no marker.
- Any message they send to you doesn't bounce or show any error.
In notification terms, the blocked person feels nothing different.
But — 5 behavioral signals they might still pick up on
LINE doesn't tell them, but the behavior changes after the block can still tip a careful person off. If you're trying to block someone quietly, these are the things to be aware of:
1. Their messages stay forever "unread"
On their side, every message they send you stays permanently unread. If they're used to you replying, and you suddenly never read anything ever again, the suspicion grows over a few days to a few weeks. For a casual contact, they'll assume you're busy. For someone who used to talk to you daily, they'll figure it out.
2. Profile photo and status freeze
After the block, they can't see any of your profile updates — avatar, status message, background, birthday, all frozen at the moment of the block. If they happen to glance at your profile, they'll notice you "haven't changed your avatar in months."
3. Your VOOM stories disappear from their feed
Anything you post to LINE VOOM is invisible to them after the block. If you post often and then suddenly vanish from their timeline, they may directly suspect a block.
4. Shared groups feel "off"
In groups you both belong to, they can still see your group messages and you theirs. But if they try to DM you privately about something from the group, and hit the same eternal "unread" wall, the block becomes obvious.
5. Mutual friends give it away
If they ask a mutual friend "have you been talking to so-and-so lately?" and find out everyone else hears back normally — only they don't — they'll deduce a block.
Tip: if you'd rather they not notice, "Hide" + "don't reply" is less obvious than blocking — but you'll still receive their messages. The full breakdown of block vs delete vs hide: LINE block vs delete friend.
Reverse question: if you check, will they know?
This is a different question. The answer depends on the method you use:
| Method | Will they notice? | Why |
|---|---|---|
| Send a paid sticker | No | Nothing reaches them on the other side |
| Create a fake group | Possibly yes | If they're online, they receive a group invite notification |
| Place a voice call | Sometimes | Their phone doesn't ring, but you leave a "called" record on your side; if they look, they see a recent call attempt |
| Watch profile / VOOM | No | Pure observation, no contact |
| Use LINE Block Checker (one-tap scan) | No | The app sends no messages, stickers, calls, or group invites |
In other words, only "fake group" and "voice call" leave a trace. Every other method (including a one-tap app scan) is invisible to the contact.
To check zero-trace, use LINE Block Checker
If you have more than a couple of contacts to check and don't want to leave any breadcrumbs, LINE Block Checker is the cleanest way. Sign in once, scan your full friend list in 5 seconds — zero messages, zero stickers, zero calls, zero group invites sent during detection.
Full step-by-step: LINE Block Checker tutorial
Frequently Asked Questions
Will the person I block on LINE get a notification?
No. LINE's official policy is that "even if you hide, block, or delete someone, they will not be notified." Their phone gets no push, no banner, nothing.
After I block them, what does their side look like when they message me?
The chat thread looks completely normal on their side. Their messages don't bounce, don't show a red exclamation, don't show any error — they just stay forever as "unread." LINE deliberately makes the block invisible to the blocked person.
If I check whether someone blocked me, will they find out?
It depends on the method. Stickers, profile checks, and the LINE Block Checker app are silent. Fake-group invites send a group notification; voice calls don't ring on their end but leave a "called" record on yours, which they could see if they look.
Will their phone get a notification when I scan with LINE Block Checker?
No. Detection sends no messages, stickers, calls, or group invites. Nothing reaches the contacts you scan — they have no way of knowing.
After I block them, can they still try to call me?
They can dial — their side will show "calling" — but the call doesn't go through. Your phone doesn't ring and you get no missed-call record. If they keep trying and never get through, they may notice.
Can I unblock someone? Will they know I temporarily blocked them?
Yes, you can unblock anyone you blocked. Open LINE → Settings → Privacy → Blocked list → tap Unblock. They get no notification and don't know about the brief block — but messages they sent during the block period don't get redelivered.
Block vs delete friend: which is harder for them to notice?
Neither sends a notification, but the reverse behaviors differ. Block: their messages to you don't reach you. Delete: their messages still reach you (you just don't see them). Full comparison: LINE block vs delete friend.
Complete guide
For the bigger picture — all detection methods, Q&A, unblock steps — start with the pillar: