Flight Crew Air Transport Pilot (ATP); Flight Crew Instrument; Flight Crew Multiengine
Flight Crew Last 90 Days 515; Flight Crew Type 15000
Distraction; Situational Awareness
Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Became Reoriented; Flight Crew Returned To Clearance
Human Factors
Flight to San Antonio. We were filed on a SID to a STAR and thus briefed the entire flight at the departure gate. I looked at the weather packet and assumed that SAT was landing on 31L. We programmed 31L into the FMC and briefed the STAR. Approaching MARKS in the descent; we were given off course vectors and several speed changes to follow traffic. We were distracted from reading the current ATIS and verifying the landing runway on the LEGS page. We flew part of the 31L transition until queried by ATC. We were on the wrong transition and were given clearance direct to a fix on the correct transition. The remainder of the approach was uneventful.The transition needs to be briefed and verified again regardless of the previous briefing at the departure gate.
[Report narrative contained no additional information.]
Air Carrier flight crew reported a track deviation on arrival into SAT after missing a runway change.