You can find them in the user manual, on the vehicle, or in the NIU APP after you've bound the scooter.

SN = serial number

VIN = frame number

In the user manual:

You will find a QR Code that holds the SN and VIN of your scooter. The SN is located at the top while the VIN is at the bottom.

In the vehicle:

For mopeds: There is a sticker with the SN under the seat part. The VIN is engraved on the scooter's frame and also under the seat part.

For kickscooters: You can find the SN on the side of the mainframe. It's under a barcode. The VIN starts with 199 and is located near the front wheel.

In the NIU APP:

In the tab 'Me', click on your device. You'll find SN and VIN there.