The BMW i3 vehicle identification number or VIN roughly follows international recognised standards ISO 3779 and ISO 4030 for North America and can be used to determine the model of BMW i3.
The BMW i3 VIN format all start with WBY. The 4th, 5th and 6th characters uniquely identify the i3 model, the numbers thereafter indicate things like year of manufacture and a unique serial number. To determine the model of i3 you therefore need to focus on the 4th to 6th digit.
The table below lists the opening 8 letters of the VIN