Technology for recognizing contact or proximity has been a key challenge in fields, such as robotic manipulation and human-robot interactions. Unlike in vision sensors, the structure and specifications of tactile and proximity sensors have not been standardized yet. Robots have various bodies depending on their purpose and environment they operate in, and physical contact in the context of robots is closely related to the means of achieving their objectives. Therefore, sensors related to state estimation naturally exhibit diverse configurations. This special issue discusses various possibilities relevant to contact and pre-touch recognition technologies. We welcome papers proposing new principles, configurations, and output information for tactile and proximity sensors, as well as system integration, interaction control, and verification through real-world tasks for their applications.