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Casio G-Shock Smart Sync

Add smart functions to your Casio square BT G-Shock Watch.
Casio G-Shock Smart Sync

What is it?
-----------
This is an unofficial app for Casio G-Shock, Edifice, and Pro Trek watches. It allows you to control your watch, sync data, and configure settings without a Casio ID. It offers a faster, privacy-focused, and more powerful alternative to the official Casio app.

Key Features check
------------------
- No Account Required: Skip the Casio ID login entirely.
- Calendar Sync: Push your calendar events (Google, Samsung, etc.) to your watch as reminders.
- Auto Timezone: Automatically adjusts watch time when you travel.
- Remote Control: Use your watch buttons to take photos, control music, or launch voice assistants.
- Alarm Sync: Configure watch alarms easily from your phone.
- Phone Finder: Trigger a loud alarm on your phone to find it.

Supported Watches
-----------------
The app works with many Bluetooth-enabled G-Shock, Edifice, and Pro Trek models.

- Square: GW-B5600, GMW-B5000, GW-5000, DW-B5600
- CasiOak: GA-B2100, GBM-2100
- G-Steel: GST-B500, GST-B400, GST-B200
- Edifice: ECB-10, ECB-20, ECB-30
- Others: GBD-800, GBD-H1000, GG-B100

Note: While these watches connect, not all specific hardware features (like fitness tracking steps on GBD models) may be fully supported yet.

App Walkthrough
---------------

1. Connection Screen
This is the first screen you see. It handles the Bluetooth connection to your watch.
- Status: Shows generic connection status.
- Scan/Connect: Automatically scans for your watch.
- Paired Devices: Lists your previously connected watches for quick access.
Connection is typically much faster than the official app (~3.5s vs 12s).

2. Time Setting
Manage your watch's timekeeping effortlessly.
- Local Time: Displays the current time from your phone.
- Send to Watch: Tap the button to sync your phone's time, timezone, and DST settings to the watch immediately.
- Home Time: Shows the 'Home' city configured on the watch.
- Battery: Displays the current battery level of the watch.

3. Alarms
Read and configure the alarms stored on your watch.
- View Alarms: See the current settings for all 5 alarms and the hourly signal (Chime).
- Edit: Tap any alarm to change its time.
- Sync: You can send these alarm settings to the watch.

4. Events (Calendar Sync)
Sync your phone's calendar to your watch!
- Upcoming Events: Lists future events from your phone's calendar.
- Send to Watch: Pushes these events to the watch's Reminder feature.
- Compatibility: Supports one-time and simple recurring events. Complex recurrence rules might show as "Incompatible".

5. Actions (Remote Control)
Turn your watch into a remote control. Assign actions to button presses on the watch.
- Find Phone: Make your phone ring loudly.
- Take Photo: Snap a picture with your phone's camera.
- Next Track: Skip music tracks on your phone.
- Voice Assist: Launch Google Assistant.
How to use: Short-press the lower-right button on the watch (when in Time mode) to trigger the selected action.

6. Settings
Configure app and watch preferences.
- Watch Settings: Adjust specific watch configurations (light duration, power saving, etc.).
- App Settings: Configure theme, behavior, and advanced options.

Where are my World Cities?
--------------------------
Using an app to manually swap between Home Time and World Time is a bit silly. Your phone already knows where you are. When setting time, this app will also set the Home Time, Timezone, and DST state to your current location. So when travelling to another timezone, just set time and you are good to go.

Build Your Own App
------------------
For those who want to build their own Android app for interfacing with the G-Shock 5000/5600 watches, I have also created an API (library) project here: https://github.com/izivkov/GShockAPI.

Similar Project
---------------
If you'd prefer not to use a mobile app but still want to set the correct time on your G-Shock, check out this Python project which can run as a server on a PC or Raspberry Pi: https://github.com/iziv

Versions

Although APK downloads are available below to give you the choice, you should be aware that by installing that way you will not receive update notifications and it's a less secure way to download. We recommend that you install the F-Droid client and use that.

Download F-Droid
  • Version 3.95 (395) suggested Added on Feb 03, 2026

    arm64-v8a armeabi-v7a x86 x86_64

    This version requires Android 8.0 or newer.

    It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.

    Permissions
    • access approximate location only in the foreground
      This app can get your approximate location from location services while the app is in use. Location services for your device must be turned on for the app to get location.
    • access Do Not Disturb
      Allows the app to read and write Do Not Disturb configuration.
    • pair with Bluetooth devices
      Allows the app to view the configuration of the Bluetooth on the phone, and to make and accept connections with paired devices.
    • access Bluetooth settings
      Allows the app to configure the local Bluetooth phone, and to discover and pair with remote devices.
    • connect to paired Bluetooth devices
      Allows the app to connect to paired Bluetooth devices
    • discover and pair nearby Bluetooth devices
      Allows the app to discover and pair nearby Bluetooth devices
    • directly call phone numbers
      Allows the app to call phone numbers without your intervention. This may result in unexpected charges or calls. Note that this doesn't allow the app to call emergency numbers. Malicious apps may cost you money by making calls without your confirmation.
    • take pictures and videos
      This app can take pictures and record videos using the camera while the app is in use.
    • run foreground service
      Allows the app to make use of foreground services.
    • run foreground service with the type "connectedDevice"
      Allows the app to make use of foreground services with the type "connectedDevice"
    • run foreground service with the type "dataSync"
      Allows the app to make use of foreground services with the type "dataSync"
    • have full network access
      Allows the app to create network sockets and use custom network protocols. The browser and other applications provide means to send data to the internet, so this permission is not required to send data to the internet.
    • change your audio settings
      Allows the app to modify global audio settings such as volume and which speaker is used for output.
    • show notifications
      Allows the app to show notifications
    • Read calendar events and details
      This app can read all calendar events stored on your phone and share or save your calendar data.
    • read the contents of your shared storage
      Allows the app to read the contents of your shared storage.
    • Companion Watch profile permission to manage watches
      Allows a companion app to manage watches.
    • run in the background
      This app can run in the background. This may drain battery faster.
    • use data in the background
      This app can use data in the background. This may increase data usage.
    • Observe companion device presence
      Allows a companion app to observe companion device presence when the devices are nearby or far-away.
    • prevent phone from sleeping
      Allows the app to prevent the phone from going to sleep.
    • modify or delete the contents of your shared storage
      Allows the app to write the contents of your shared storage.
    • com.android.alarm.permission.DISMISS_ALARM
    • set an alarm
      Allows the app to set an alarm in an installed alarm clock app. Some alarm clock apps may not implement this feature.
    • org.avmedia.gshockGoogleSync.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 18 MiB PGP Signature | Build Log

  • Version 27.4 (274) - Added on Jan 19, 2026

    arm64-v8a armeabi-v7a x86 x86_64

    This version requires Android 8.0 or newer.

    It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.

    Permissions
    • access approximate location only in the foreground
      This app can get your approximate location from location services while the app is in use. Location services for your device must be turned on for the app to get location.
    • access Do Not Disturb
      Allows the app to read and write Do Not Disturb configuration.
    • pair with Bluetooth devices
      Allows the app to view the configuration of the Bluetooth on the phone, and to make and accept connections with paired devices.
    • access Bluetooth settings
      Allows the app to configure the local Bluetooth phone, and to discover and pair with remote devices.
    • connect to paired Bluetooth devices
      Allows the app to connect to paired Bluetooth devices
    • discover and pair nearby Bluetooth devices
      Allows the app to discover and pair nearby Bluetooth devices
    • directly call phone numbers
      Allows the app to call phone numbers without your intervention. This may result in unexpected charges or calls. Note that this doesn't allow the app to call emergency numbers. Malicious apps may cost you money by making calls without your confirmation.
    • take pictures and videos
      This app can take pictures and record videos using the camera while the app is in use.
    • run foreground service
      Allows the app to make use of foreground services.
    • run foreground service with the type "connectedDevice"
      Allows the app to make use of foreground services with the type "connectedDevice"
    • run foreground service with the type "dataSync"
      Allows the app to make use of foreground services with the type "dataSync"
    • have full network access
      Allows the app to create network sockets and use custom network protocols. The browser and other applications provide means to send data to the internet, so this permission is not required to send data to the internet.
    • change your audio settings
      Allows the app to modify global audio settings such as volume and which speaker is used for output.
    • show notifications
      Allows the app to show notifications
    • Read calendar events and details
      This app can read all calendar events stored on your phone and share or save your calendar data.
    • read the contents of your shared storage
      Allows the app to read the contents of your shared storage.
    • Companion Watch profile permission to manage watches
      Allows a companion app to manage watches.
    • run in the background
      This app can run in the background. This may drain battery faster.
    • use data in the background
      This app can use data in the background. This may increase data usage.
    • Observe companion device presence
      Allows a companion app to observe companion device presence when the devices are nearby or far-away.
    • prevent phone from sleeping
      Allows the app to prevent the phone from going to sleep.
    • modify or delete the contents of your shared storage
      Allows the app to write the contents of your shared storage.
    • com.android.alarm.permission.DISMISS_ALARM
    • set an alarm
      Allows the app to set an alarm in an installed alarm clock app. Some alarm clock apps may not implement this feature.
    • org.avmedia.gshockGoogleSync.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 18 MiB PGP Signature | Build Log

  • Version 27.3 (273) - Added on Jan 14, 2026

    arm64-v8a armeabi-v7a x86 x86_64

    This version requires Android 8.0 or newer.

    It is built and signed by F-Droid, and guaranteed to correspond to this source tarball.

    Permissions
    • access approximate location only in the foreground
      This app can get your approximate location from location services while the app is in use. Location services for your device must be turned on for the app to get location.
    • access Do Not Disturb
      Allows the app to read and write Do Not Disturb configuration.
    • pair with Bluetooth devices
      Allows the app to view the configuration of the Bluetooth on the phone, and to make and accept connections with paired devices.
    • access Bluetooth settings
      Allows the app to configure the local Bluetooth phone, and to discover and pair with remote devices.
    • connect to paired Bluetooth devices
      Allows the app to connect to paired Bluetooth devices
    • discover and pair nearby Bluetooth devices
      Allows the app to discover and pair nearby Bluetooth devices
    • directly call phone numbers
      Allows the app to call phone numbers without your intervention. This may result in unexpected charges or calls. Note that this doesn't allow the app to call emergency numbers. Malicious apps may cost you money by making calls without your confirmation.
    • take pictures and videos
      This app can take pictures and record videos using the camera while the app is in use.
    • run foreground service
      Allows the app to make use of foreground services.
    • run foreground service with the type "connectedDevice"
      Allows the app to make use of foreground services with the type "connectedDevice"
    • run foreground service with the type "dataSync"
      Allows the app to make use of foreground services with the type "dataSync"
    • have full network access
      Allows the app to create network sockets and use custom network protocols. The browser and other applications provide means to send data to the internet, so this permission is not required to send data to the internet.
    • change your audio settings
      Allows the app to modify global audio settings such as volume and which speaker is used for output.
    • show notifications
      Allows the app to show notifications
    • Read calendar events and details
      This app can read all calendar events stored on your phone and share or save your calendar data.
    • read the contents of your shared storage
      Allows the app to read the contents of your shared storage.
    • Companion Watch profile permission to manage watches
      Allows a companion app to manage watches.
    • run in the background
      This app can run in the background. This may drain battery faster.
    • use data in the background
      This app can use data in the background. This may increase data usage.
    • Observe companion device presence
      Allows a companion app to observe companion device presence when the devices are nearby or far-away.
    • prevent phone from sleeping
      Allows the app to prevent the phone from going to sleep.
    • modify or delete the contents of your shared storage
      Allows the app to write the contents of your shared storage.
    • com.android.alarm.permission.DISMISS_ALARM
    • set an alarm
      Allows the app to set an alarm in an installed alarm clock app. Some alarm clock apps may not implement this feature.
    • org.avmedia.gshockGoogleSync.DYNAMIC_RECEIVER_NOT_EXPORTED_PERMISSION

    Download APK 18 MiB PGP Signature | Build Log