Learn how to deregister your phone number from iMessage if you no longer use Apple’s messaging service and have switched to an Android phone.

Switching from iPhone to Android is easy. However, even after putting your SIM card in your Android phone, you may not receive SMS/MMS text messages that your friends and family send from their iPhones. This is because their iPhone may still think your phone number is registered with iMessage, and try to send a blue iMessage instead of a green SMS.
Thankfully, it’s easy to remove your phone number from iMessage so that there are no issues receiving standard text messages once you move from an iPhone to a non-Apple phone.
Disable your phone number for iMessage if you still have your iPhone
1) Ensure the SIM card/eSIM is working on your iPhone and it’s connected to Wi-Fi or cellular data.
2) Open the iOS Settings app and tap Apps from the bottom.
3) Select Messages from the list of applications and turn off iMessage.

4) Go back to the previous Settings page and tap FaceTime from the list of applications. Then, just like iMessage, turn off the switch for FaceTime to disable Apple’s video and audio calling service.
This should disable iMessage and FaceTime, thus deregistering your phone number from Apple’s exclusive messaging and calling service. Now, you can insert this SIM card into your Android phone or a feature phone without having issues related to receiving SMS text messages or MMS.
How to deregister phone number from iMessage if you don’t have your iPhone anymore
1) Visit Apple’s Deregister iMessage page on your smartphone, tablet, or computer.
2) Scroll down to the ‘No longer have your iPhone?’ section.
3) Select your country and enter the phone number you want to deregister.
4) Enter the captcha code from the image and hit Send Code. Hit Refresh Code if you don’t see the captcha image.
5) Finally, enter the confirmation code Apple sends you and click Submit.
Your phone number should now be removed from iMessage, and you’ll now receive text messages without any issue.
Note that in rare cases, it may take a few hours for some Apple devices (such as those belonging to family members and friends) to recognize that your phone number is no longer registered with iMessage.
Problems with SMS after switching from iPhone to Android…
Since iMessage launched in 2011, users switching away from iPhone have complained of issues receiving text messages from other Apple devices. The problem is that if an iPhone sees a number still attached to iMessage, it will try to send an iMessage, not an SMS.
The issue has been well-documented and widespread, as evidenced by this Apple support forum. One user had become so upset over the matter that she filed a lawsuit against the company, specifically looking for class action status.
Hopefully, you won’t have to go that far, and if you follow the steps mentioned above, you’ll probably be successful in getting rid of iMessage once and for all.
Also, check out: 10 Android features I miss on my iPhone