This dataset comprises a tandem mass tag (TMT)–based quantitative proteomic analysis of proteins proximal to SYCP1 identified using BioID proximity labelling. Two independent BioID experiments were performed using distinct SYCP1 constructs: an N-terminal Myc-tagged SYCP1 and a C-terminal HA-tagged SYCP1. For each construct, full-length wild-type SYCP1, a SYCP1 deletion mutant lacking amino acids 918–942, and a SYCP1 knockout negative control were analysed in MCF7 cells. Biotinylated proteins were enriched by streptavidin-based affinity purification, and the resulting protein lysates were submitted to the EMBL Proteomics Core Facility for downstream processing and LC–MS/MS analysis, enabling quantitative comparison of SYCP1-associated proteins across constructs and conditions.