Phone Guardian: Left-Behind icon

Phone Guardian: Left-Behind

まもるくん:スマホ置き忘れ防止

Phone Guardian: Left-Behind is #10 in Utilities Paid in Japan and charting in 1 of 16 countries we track.

DeveloperKAZUTO MATSUBARA
CategoryUtilities
Price300 JPY
Released
Rating★ 3.9 (7)
Version1.2
Age rating4+
First charted🇯🇵 25 Sep 2026

Where it ranks now

Every top chart it appears in across 16 countries.

CountryChartRank
🇯🇵 JapanUtilities · Paid#10
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Estimated downloads and revenue, ratings momentum, rank history, recent reviews per country and breakout scores for Phone Guardian: Left-Behind.

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About Phone Guardian: Left-Behind

"Wait — where's my phone?" Let's make that heart-drop moment a thing of the past.

Phone Guardian buzzes your Apple Watch the instant the Bluetooth link to your iPhone breaks. Find My helps you locate a phone after it's lost — Phone Guardian tells you the second you leave it, so you can just turn around.

■ Perfect for moments like these
- Heading out: know the second you leave your phone at the door
- Cafés & restaurants: never leave it on the table when you get up
- Travel & trips: avoid leaving it at hotels or airports
- Trains & buses: get alerted the moment you leave it on your seat

■ Key features
- Instant left-behind alert: your Watch buzzes within seconds
- Distance warning: a gentle heads-up before the connection is even lost
- False-alarm guard: a brief blip won't trigger it (0–10s grace)
- Safe Zones: silence alerts at home or any place you choose
- Ring your iPhone: find it loudly from your Watch, even in silent mode
- Also a watch face: turn the monitoring screen into a digital or analog clock, with your own photo background, world clock, and corner widgets
- Japanese / English: switch anytime inside the app

■ Battery friendly
Only low-energy Bluetooth and near-zero-power geofencing. No constant GPS — battery impact is minimal.

■ Privacy
No location, no analytics, nothing leaves your device. Everything stays local.

■ Before you start
- Requires an iPhone on iOS 17+ paired with an Apple Watch on watchOS 9+
- One-time purchase. No subscription, no ads.
- Due to watchOS rules, alerts can be delayed on some models or usage patterns. If that happens, keeping Phone Guardian as your Watch face is the most reliable setup — and it doubles as your everyday clock.

Keep your iPhone safe, right there on your wrist.

Latest updates

1.2
[Important Bug Fix] Fixed an issue where notifications could occasionally stop working after adding or removing a Safe Zone. [Apple Watch] Notifications can be received by vibration even when the MamoruKun app is not displayed on Apple Watch. You can continue using your favorite watch face as usual.