Is it possible to track a phone without a SIM card?

Oh my, this is all so confusing to me! I’ve been wondering about this too because my grandson sometimes takes his SIM card out when he doesn’t want to be reachable. I worry about his safety, you know?

So if I understand right from what Alex said, the phone can still show where it is through GPS satellites, but it needs Wi-Fi to actually tell someone the location? And Nooneshere mentioned “consent-based” tools - does that mean I should ask my grandson’s permission first before setting up any tracking? I want to keep him safe but I also don’t want to overstep boundaries. This technology is harder to understand than I expected!