This study examines how the perceptions that twelve teachers of Japanese as a second language (L2) had of extensive reading (ER) changed following 10 months of online English ER. Interviews provided much of the study data, supported by pre-project and post-project questionnaires. The participants' pre-project and post-project vocabulary sizes and reading rates were measured to examine whether changes in their perceptions coincided with their linguistic change. The participants' usage of ER led to their discovering the power of ER in overcoming psychological barriers toward L2 reading, the difficulty of routinizing reading, the importance of facilitators' support, and the benefits of occasional dictionary use. While their reading rate gains corresponded with their unchanged high rating of ER's benefits for reading skills, their vocabulary growth did not correspond with their decreased rating of ER's benefits on vocabulary development. Furthermore, the participants agreed that teachers are learners' role models more after the project.