Languages differ in how they mark prosodic focus–whether syntactically/morphologically or phonetically/phonologically or both, which bears important implications for bilingual language acquisition. This study presents data on subject prosodic focus marking by L1 English/L2 Japanese, heritage Japanese speakers and L1 Japanese speakers. English primarily marks subject focus prosodically with stress and pitch fall, while Japanese also uses an obligatory postpositional particle, /-ga/. Fundamental frequency (F0) is used for subject focus in both languages, but intensity is used more consistently in English. Previous studies have examined L1 Japanese/L2 English production of subject focus, but there is little data looking at L1 English/L2 Japanese, and even less examining heritage Japanese speakers. Data was collected using a semi-spontaneous production task. Results show that i) L2 speakers used intensity more than the other groups; ii) HS speakers used a greater degree of F0 fall than the other groups, and the fall was greater when the /-ga/ focus particle was present; iii) the L1 speakers tended to employ greater F0 fall when the particle was absent. These results suggest that L2 learners transfer L1 prosodic cues to their L2. Heritage speakers, however, combine prosodic marking strategies from their dominant and non-dominant languages.