Clarke moved to Ceylon (later Sri Lanka), initially for diving and underwater photography. He found the tropical environment conducive to his writing and exploration interests. He eventually became a resident.

Clarke became an avid scuba diver and underwater photographer, exploring the coral reefs and shipwrecks around Sri Lanka. This experience provided inspiration for his fiction and non-fiction writing, including "The Deep Range" and "The Reefs of Taprobane".

With his friend Mike Wilson, Clarke founded the Underwater Safaris diving company, which was based in Trincomalee, Sri Lanka. The company offered diving tours and allowed them to explore the ocean for pleasure and research.

Clarke began hosting the television series "Arthur C. Clarke's Mysterious World", which explored unexplained phenomena and scientific mysteries. Filming often took place in Sri Lanka, showcasing the country's beauty and Clarke's expertise.