Agents were searching communities including Puna and Pahoa for the 36-year-old fugitive, Mauinow.com reported Tuesday.
"He may or may not actually be on Hawaii Island, but we are taking this lead seriously out of genuine concern for local residents," Honolulu FBI Special Agent Tom Simon said.
San Diego is wanted by the FBI on charges for his alleged involvement in the bombing of two buildings in the San Francisco area Aug. 28, 2003.
The FBI has offered a $250,000 reward for information leading to San Diego's arrest.
"We hope that people on the Big Island may like the idea of $250,000 more than they like having an accused bomber hiding in their community," Simon said. "It's important to recognize that this guy is considered armed and dangerous. If you know where he is, please just call it in. We don't want anyone getting hurt trying to be a hero."