Recurrence is a major cause of death among BRCA1/2 mutation carriers with breast (BrCa) and ovarian cancers (OvCa). We performed multi-omic sequencing on 67 paired primary and recurrent BrCa and OvCa from 27 BRCA1/2 mutation carriers to identify potential recurrence-specific drivers. PARP1 amplifications were identified in recurrences (FDR q = 0.05), and PARP1 was significantly overexpressed across primary BrCa and recurrent BrCa and OvCa, independent of amplification status. RNA-seq analysis found two BRCA2 isoforms, BRCA2-201/Long and BRCA2-001/Short, predicted sensitive and insensitive to nonsense-mediated decay, respectively. BRCA2-001/Short was expressed more frequently in recurrences and associated with reduced overall survival in breast cancer (87 vs. 121 months; HR = 2.5 [1.18–5.5]). Loss of heterozygosity (LOH) status was discordant in 25% of patient’s primary and recurrent tumors, with switching between both LOH and lack of LOH found. Our study revealed multiple potential drivers of recurrent disease in BRCA1/2 mutation-associated cancer, improving our understanding of tumor evolution and suggesting potential biomarkers.