A foreign drone was in Indonesian waters close to Natuna Island, an air force official said on Friday.
The drone was discovered on Thursday evening in Riau province's waters and brought to the air force base, Spokesman of Indonesian Air Force Dwi Badarmanto said.
"It is not our aircraft. We are trying to find the owner," he told Xinhua news agency.
The drone will be brought to the air force research centre in West Java province for further probe, Badarmanto added.