CALSTAR (California Shock Trauma Air Rescue) was founded in 1983 and commenced air ambulance operations with a leased BK117 in 1984 in San Mateo. The non-profit company operated MBB Bo 105LS and MD900s in its early years and ordered eight EC135s in 2012. CALSTAR was acquired by for-profit competitor REACH, a subsidiary of Air Medical Group Holdings, in 2016. Then, Air Medical Group Holdings merged with American Medical Response to form Global Medical Response in 2018. CALSTAR and REACH have about 32 EMS helicopter bases in CA, including the Sutter Health Memorial Medical Center in Modesto.

Calstar (California Shock-Trauma Air Rescue) operates a number of air ambulances bases in northern California equipped with Airbus EC135s. This EC135P2+ was based at Salinas Municipal Airport and is crewed with a pilot, flight nurse and flight paramedic.

Not-for-profit Sutter Health operates twenty-four hospitals in Northern California. This EC-135 has been flown by Calstar for the Critical Care Network since delivered in 2017.

Originally delivered in 1986 as a Bölkow 105CBS-2 (ex D-HDXL), and later converted to 105CBS-4.

CALSTAR 8 is based at Vacaville.