The history of Achencoil is deeply intertwined with the legend of Lord Ayyappan. It is believed that Parasurama, the sixth avatar of Vishnu, installed the idol of Lord Ayyappan here. The temple's unique tradition includes the presence of two deities alongside Lord Ayyappan: Purna and Pushkala, representing his consorts. Historically, the region was under the control of various dynasties, including the Pandyan and Travancore kingdoms, each contributing to the temple's development and maintenance. The temple has been a significant pilgrimage site for centuries, attracting devotees from across South India. Over time, the temple has undergone renovations and expansions, preserving its ancient traditions and architectural heritage.