A transparent display allows the presentation of images and information while simultaneously transmitting background light. Unlike conventional displays, it enables users to obtain information while visually confirming their surroundings. For instance, a transparent display equipped with a speech transcription system allows users to read transcribed conversation content while observing the facial expressions and gestures of their conversation partners, thereby enhancing comprehension. However, because users frequently shift their visual focus between the background and the overlaid text, a time lag may occur in acquiring textual information, potentially hindering smooth communication. Therefore, it is essential to clarify which methods of presenting information remain easily recognizable even when out of focus. This study focuses on fonts, the fundamental components of textual information, to investigate which fonts are more easily recognized under defocused conditions. An experiment was conducted to evaluate the visibility of fonts on a transparent display at various focal distances, using two character types with differing visual complexity (Kanji and the Latin alphabet). The results revealed that the visibility of text on a transparent display is influenced by factors such as font type, degree of defocus, and character type. Notably, differences in font visibility became particularly pronounced under moderate defocus.