B737 Undifferentiated or Other Model
Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Conflict Airborne Conflict; Deviation / Discrepancy - Procedural Published Material / Policy; Deviation / Discrepancy - Procedural FAR
General None Reported / Taken
Human Factors; Airspace Structure; Procedure
On approach to SAN we saw what appeared to be a drone or unidentified aircraft crossing our flight path. We called it and were asked what altitude. We replied possibly 5000 feet or 6000 feet MSL. We were issued to fly LOC 27 or RNAV 27 after LUCKI Arrival and keep the speed up. We closed the loop and remarked about the [weather] south of the border and were both curious what a large drone would have been doing. About 5000 feet on arrival; we were questioned as to our track and asked if we had the field in sight. We replied yes and after landing were asked to contact ATC.
Air Carrier Captain reported a drone sighting while established on arrival to SAN.