The Orange County Sheriff's Department and the U.S. Coast Guard hauled in the bales Sunday afternoon about 15 miles out from Dana Point Harbor.
The county officers turned over more than 7,000 pounds of pot valued at more than $3 million to the U.S. Border Patrol, The Orange County Register reported. The total didn't include the marijuana recovered by the Coast Guard.
Authorities made no arrests and it was unknown how the marijuana bales wound up floating at sea, the newspaper said.
Border Patrol spokesman Michael Jimenez said the case was unusual in that the bales apparently were not tossed overboard while a vessel was being pursued by authorities.
"At other events, they've dumped the bales to get rid of weight if they're being chased," he said. "Generally in these cases we're aware they're being dumped. What's more unusual is that the bales were floating with no boat in sight."