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Bonamia(Haplosporida) are oyster parasites capable of devastating oyster populations. The near-circumglobal distribution of the host generalistB. exitiosahas previously been associated with the natural and anthropogenic dispersal of broadly distributed non-commercial oysters in theOstrea stentinaspecies complex. Here, we took a global snapshot approach to explore the role of the widely introduced Pacific oysterMagallana gigas, a commercially important species that can be found on every continent except Antarctica, in transportingBonamia.We screened 938M. gigasindividuals from 41 populations in this oyster’s native and non-native geographic range for presence ofBonamiaDNA using PCR.B. exitiosawas the only species detected and only within 2 of 5 populations from southern California, USA (10 and 42% PCR prevalence). Therefore,M. gigascould have played a role in transportingB. exitiosato California (if introduced) and/or maintainingB. exitiosapopulations within California, but morphological confirmation of infection needs to be done to better understand the host-parasite dynamics within this system. We detected noBonamiaDNA within any other non-nativeM. gigaspopulations (n = 302) nor within nativeM. gigaspopulations in Japan and Korea (n = 582) and thus found no evidence to support the co-dispersal ofM. gigasand otherBonamiaspecies. Lower sample sizes within some populations and the non-systematic nature of our sampling design may have led to false negatives, especially in areas whereBonamiaare known to occur. Nevertheless, this global snapshot provides preliminary guidance for managing both natural and farmed oyster populations.