2. You do not need a SIM card to log in. The app is not connected to your phone number, so you can use it on devices such as tablets without needing a SIM card.
Accordingly, do you have to have a phone number to use Snapchat?
The phone number associated with your Snapchat account can be changed. New Snapchat accounts can also be created without entering a phone number at all. Open the Snapchat app, login and tap the Settings icon in the upper right corner.
Can you have 2 Snapchat accounts with the same phone number?
One is able to use the same number for more than one Snapchat account, yes, but only the most recent account will have that number listed in Settings, and can use the “Friend Finder” feature. Only one email can be used per Snapchat account, however. (I have verified this in two different Snapchat accounts.)