To subscribe for Airtel 4G follow the steps bellow:
Step 1: Get a 4G enabled device, you can’t use Airtel 4G without a device that has 4G Antena
Step 2: Buy Airtel 4G SIM or Upgrade your SIM to 4G by dialing *121#
Step 3: Be withing Airtel 4G coverage locations to enjoy the service
Airtel will give you 25% data bonus every time you activate a data plan of N500 and above for 3 months.