While absolute pitch (AP)—the ability to identify musical pitches without external reference—is rare even in professional musicians, anecdotal evidence and case-report data suggest that some musicians without traditional AP can nonetheless better name notes played on their musical instrument of expertise than notes played on instruments less familiar to them. We have called this gain in AP ability “instrument-specific absolute pitch” (ISAP). Here, we report the results of the first two experiments designed to investigate ISAP in professional oboists. In Experiment 1 (n = 40), superiority for identifying the pitch of oboe over piano tones varied along a continuum, with 37.5% of oboists demonstrating significant ISAP. Variance in accuracy across pitches was higher among ISAP-possessors than ISAP-non-possessors, suggestive of internalized timbral idiosyncrasies, and the use of timbral cues was the second-most commonly reported task strategy. For both timbres, both groups performed more accurately for pitches associated with white than black piano keys. In Experiment 2 (n = 12), oboists with ISAP were less accurate in pitch identification when oboe tones were artificially pitch-shifted. The use of timbral idiosyncrasies thus may constitute a widespread mechanism of ISAP. Motor interference, conversely, did not significantly reduce accuracy. This study offers the first evidence of ISAP among highly trained musicians and that reliance on subtle timbral (or intonational) idiosyncrasies may constitute an underlying mechanism of this ability in expert oboists. This provides a path forward for future studies extending the scientific understanding of ISAP to other instrument types, expertise levels, and musical contexts. More generally, this may deepen knowledge of specialized expertise, representing a range of implicit abilities that are not addressed directly in training, but which may develop through practice of a related skill set.