Join a Group FaceTime Call from iMessage in iOS 12

Apple's iOS 12 introduced Group FaceTime, allowing up to 32 participants to chat simultaneously. When a call is initiated inside an existing iMessage thread, you do not need to answer an incoming ring to participate. Instead, members of the group can seamlessly hop into the live conversation directly from the Messages app at any point while the call remains active.

Steps to Join the Active Call

1. Open Messages: Launch the Messages app on your iPhone or iPad running iOS 12.
2. Select the Group Thread: Tap on the specific group iMessage conversation where the call is taking place.
3. Locate the Call Bubble: Look through the conversation timeline. You will see a large, distinct message bubble indicating that a FaceTime call has started, showing the number of active participants.
4. Tap Join: Tap the green Join button inside the message bubble.

Alternative Method via Group Details

If the chat is busy and the call bubble has scrolled out of view, you can join using the header:

1. Tap the contact icons and names at the very top of the group message screen.
2. An expanded menu will appear showing options for audio, FaceTime, and info.
3. Tap the green FaceTime or Join icon that appears beneath the contact names.

Once selected, iOS 12 will automatically open the FaceTime interface and connect your video and microphone to the ongoing group session.