Earplugs are widely used to prevent noise-induced hearing loss, but discomfort can reduce their effectiveness by affecting their consistent and proper use. Earplug comfort can be described by four dimensions: physical (biomechanical and thermal interactions with the earcanal), acoustical (noise/useful sound perception), functional (usability and efficiency), and psychological (well-being and satisfaction). (Dis)comfort results from the interplay within the user/earplug/work environment triad. The components of this triad and their interactions across multiple phases, ultimately shape the comfort judgment and are defined by various physical and psychological characteristics that must be assessed to fully understand comfort. This paper targets acoustical characteristics of both disposable and reusable earplugs when inserted in the earcanal, focusing on indicators such as sound attenuation and occlusion effect. It presents a synthesis of various acoustic comfort testers developed by the authors’ research team to assess these characteristics. Virtual and physical truncated realistic artificial ears and whole head are explored. This research aims to provide manufacturers with comfort-driven design methods for earplugs.