Using a Google Account:

NOTE: You can sync the contacts on your HTC device with your Google account, and then re-sync the contacts from the account with your Samsung Galaxy S Duos 3. To do so:

  1. Sign in with your Google account on the HTC device
  2. Go to the phone’s “Settings” menu and tap “Accounts & Sync” under “Personal
  3. Tap “Google” and select the desired account
  4. Tap “Menu” > “Sync all”, or alternatively clear and re-check the “Contacts” box
  5. Switch to the Samsung device and register the same Google account on it
  6. Next, go to “Settings” and tap "Accounts” under “User and Backup
  7. Select your Google account, press “Menu” > “Sync all

Via “People” / “Contacts” (Export / Import):

NOTE: Using the default “People” and “Contacts” applications on the HTC and Samsung devices, you can export the contacts on the One X / X+, transfer the backup file via email or using a PC, and import it on the S Duos 3.

  1. Open “People” on the HTC device
  2. From the “People” tab press “Menu” > “manage contacts
  3. Tap “Import / Export contacts” > “Export to phone storage
  4. Select an account and make sure you remember the backup file’s name before tapping “OK
  5. Open the email application and compose a new email
  6. Attach the backup file to the email and send it to your own Gmail address
  7. Switch to the Samsung Galaxy S Duos 3 and open the email, then download the attached file
  8. Launch “Contacts”, press “Menu” > “Import / Export” > “Import from SD card
  9. If necessary, select an account to import the contacts on, and load the vCard file

NOTE: Alternatively you can transfer the VCF file from one phone to the other by connecting both devices to a computer via USB.

Using “Send Anywhere”:

NOTE:Send Anywhere” is a third party app that can be used to transfer contacts and other types of files (even cross platform) through a P2P connection. This method doesn’t require a computer.

  1. Visit the Play Store and install Send Anywhere on both smartphones
  2. Open the app on both devices
  3. On the HTC One X / X+, tap “Send” > “Contacts
  4. Select the contacts you want to share and tap “Send
  5. Lastly, choose a method of transfer You can use a QR code to start the transfer, or you can manually enter the transfer code generated randomly on the sender device (in this case the HTC)

See More: Transfer Contacts from an HTC One X / X+ to a Samsung Galaxy S Duos 3