The flashlight is the most vital tool in Calling. Without it, the character's health drops to a cautionary Yellow. The flashlight is picked up by Shin in the one-story house, by Rin in the school, and by Makoto in the beauty parlor. Chiyo does not require a flashlight in her scenarios because everything is brighter (with a kind of ethereal glow) than the others' scenarios.

The flashlight also is crucial to have while searching and examining the area. Without it, characters will not be able to "see" and pick up items, read notes, or thoroughly examine items. Sometimes during the levels, the battery on the flashlight dies, and the character must find new batteries to replace them in order to progress. But when the flashlight is off, the player can see hidden phone keys (with white Japanese symbols, or Kanji, on them), where if the flashlight was on some of the keys wouldn't be visible. In addition to some keys appearing in the dark, some words appear as well. In one instance, in the hospital where sound could be recorded, a spot on the wall (near the beds on the right of the room) away from the recording area showed symbols pertaining to the keys when the flashlight was turned off.