The LG G5 uses a Nano-SIM card. See your local carrier for any SIM related needs.
Inserting and removing Nano-SIM card
Using the ejetor tool or pin, open the remove the SIM card tray.
Insert Nano-SIM card so that the metal connector faces down with the tabbed side first as shown above.
Things to know about LG G5 Nano-SIM card
You can set lock on Nano-SIM card so that others cannot use. For questions regarding Nano-SIM card usage, contact your carrier.
Take care when inserting or removing the Nano-SIM card from the device.
Cautions for Nano-SIM card usage
If Nano-SIM card is damaged by scratch, bending, or magnet, the files stored in Nano-SIM card may be erased, or product may malfunction.