Open the Phone app
Dial `*#*#4636#*#*`
Tap Phone information
Check the network type and supported bands if shown
Go to Settings
Tap About phone
Check the model number and region variant
Look up the Nothing Phone 3a specifications for your exact model
Check the box, invoice, or carrier listing for supported bands
Use a third-party app like NetMonster or LTE Discovery
Insert your SIM and check the connected LTE/5G band in the app
Contact Nothing support with your IMEI or model number
Check your carrier’s band compatibility page for your network and region