How can I find my lost iPhone without SIM-card?

In order to locate it using Find My, it must have an Internet connection. That means it must be powered on and connected to WiFi if it has no SIM.

Newer models (beginning with the iPhone 12, I believe) can report their location using the Find My network, even when powered off, so long as the battery is not completely dead.

If your iPhone or iPad is lost or stolen - Apple Support

Start here: If your iPhone or iPad is lost or stolen - Apple Support

iPhone 6+ find out

My iPhone is missing

how can i find my lost iphone 11

how can i find my lost iphone