Mine are indoor only. Emily and Charlie were strays off the street and have absolutely NO interest in going outside. Tanner has always been an indoor kitty and only goes out in a harness. Bear has always been an indoor kitty also. None of them show any interest in going outside. I can hold the door open and they will run in the opposite direction. I suppose if I left it open long enough they might go outside, but I am not going to tempt fate