Small Aircraft
Air Traffic Control Fully Certified
Communication Breakdown; Time Pressure
ATC Issue All Types; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter CFTT / CFIT
Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert
Human Factors
Aircraft X was advised to expect a single turn on to final - aircraft was tighter on the approach than necessary in an effort to squeeze him in front of 3 faster aircraft inbound to ZZZ. Aircraft X was number 1; descending to 031. Shortly afterward; the single turn to final was issued; clearance for the RNAV Runway 29 SBP issued; and the clearance read back. I took care of other duties while keeping an eye on the [aircraft]. I noticed he went through final; advised him my turn on might have been a little later/too tight; and issued a heading of 280 to get him back onto the approach course. I made a transmission or two to other aircraft; then observed Aircraft X was tracking something closer to a 290 north of the RNAV 29 final approach course; very close to the 3;500 foot MVA (Minimum Vectoring Altitude) around 5 mile final for SBP. I advised the aircraft to turn right heading 020 immediately and expedite climb to 035 due to high terrain. Aircraft X read back correctly; but did not begin the turn until appearing to be just inside of the eastern line of the 035 foot MVA. At this time I realized as he was turning he was heading towards a higher 4;400 foot MVA; so I issued another immediate turn to 110 for terrain with a climb to 4;500 feet. The turn was made; the aircraft climbed; and he was placed just over 3 miles north of the 2 jets inbound to SBP. He was re-sequenced to be number 3; with no additional issues on his approach.  Ensure aircraft comply with instructions in a timely manner and issue instructions with time enough for pilots to comply before MVA's are a factor.
SBA TRACON Controller reported pilot making late turns while vectoring aircraft onto RNAV final resulting in entering areas of higher MVA.