Japan is exposed to a broad range of different service conditions from snow, to wind, to maritime pollution, to seismic events, to volcanic activity. Given this, local power companies have been active in R&D to deal with these threats and succeeded in establishing a system with very high reliability. Polymer insulators were first installed here as interphase spacers, later as jumper supports and then in tension/suspension applications. Long-term reliability of these insulators has been closely monitored since their first installation during the 1990s. This presentation reviews the history of polymer insulator application in Japan and explains how this technology has resulted in their broader use throughout the country.