Yes, you must be a Colorado resident to purchase recreational marijuana in Colorado.
Non-residents cannot legally buy recreational cannabis. Some mistakenly believe a US passport suffices—it does not. Dispensaries scan IDs; out-of-state licenses are rejected.
Note: Possession limits (1 oz flower, 8g concentrate, 800mg edibles) apply to residents. Consumption only on private property (not hotels, cars, public). Transport across state lines is federal crime.