Usually LTE is enabled by default on devices. Sometimes it can be turned off when travelling internationally, troubleshooting or even simply accidentally changing the setting.
How to enable LTE on an Apple device
To enable LTE on an iPhone or an iPad running iOS 10.3 and later:
Go to
Settings
Select
Cellular
Select
Cellular data options
Select
Enable LTE
Select
Voice & Data
To enable LTE on an iPhone or an iPad running an earlier iOS version:
Go to
Settings
Select
Cellular
Select
Cellular data options
Toggle
Enable LTE
How to enable LTE on an Android device
On Android, the settings vary slightly from one model to another and to one Android operating system to another. Below you will find the most common settings found to enable LTE.
LG G5 running Nougat 7.0.0
Go to
Settings
Select
Wireless networks
Select
More
Select
Mobile Networks
Select
Network mode
Select
GSM/WCDMA/LTE auto
LG G4 running Marshmallow 6.0.0
Go to
Settings
Select
Wireless Networks
Select
More
Select
Mobile Networks
Select
System select
Select
Network mode
Select
LTE/GSM/UMTS
LG G4 running Lollipop 5.1.0
Go to
Settings
Select
Connectivity
Select
More
Select
Mobile networks
Select
Network mode
Select
GSM/WCDMA/LTE auto
Moto Z running Nougat 7.0.0
Go to
Settings
Select
Wireless & networks
Select
More
Select
Mobile networks
Select
Preferred network type
Select
LTE
Moto Z running Marshmallow 6.0.1
Go to
Settings
Select
Wireless & networks
Select
More
Select
Cellular networks
Select
Preferred network type
Select
LTE
Samsung Galaxy S8 running Nougat 7.0.0
Go to
Settings
Select
Connections
Select
Mobile Networks
Select
Network mode
Select
LTE/WCDMA/GSM (auto connect)
Samsung Galaxy S6 running Marshmallow 6.0.1 or Lollipop 5.0.2