Check whether both JBL speakers support JBL Connect, JBL Connect+, or PartyBoost
Turn on both JBL speakers
Put both speakers in pairing mode if needed
Connect your iPhone to the first JBL speaker via Bluetooth
Open the JBL app if your speaker model supports it
Use the app or speaker buttons to link the second JBL speaker
If your model supports stereo pairing, select Left and Right speaker roles in the app
If your model supports PartyBoost or Connect+, press the connect button on both speakers to pair them together
If your speakers do not support linking, connect only one speaker to the iPhone at a time
Keep the speakers close to each other during pairing
Make sure both speakers are charged
Disconnect other Bluetooth devices if pairing fails
Restart the speakers and try again if needed