Abstract: This study investigates the latest satellite-derived sea ice data from National Snow and Ice Data Center (NSIDC) to analyze the seasonal variation for spatial trends of Antarctic sea ice from 1979 to 2014. It also examines the relative contributions of the Interdecadal Pacific Oscillation (IPO) and Atlantic Multidecadal Oscillation (AMO) phase shifts to these trends, along with the associated mechanisms. Results indicate that SIC (sea ice concentration) in the Ross Sea and the South Indian Ocean showed increasing trends across all four seasons from 1979 to 2014. During warm seasons (December to May), SIC decreased significantly in the Amundsen–Bellingshausen Seas and increased in the Weddell Sea, resembling a positive phase of the Antarctic Dipole (ADP). Conversely, during cold seasons (June to November), SIC trends in the Amundsen–Bellingshausen–Weddell Seas displayed a negative phase of ADP. Likewise, annual and seasonal Antarctic sea ice extent (SIE) exhibited significant upward trends. The IPO’s phase transition from a positive to negative (1979–2014) intensified the Amundsen Sea Low (ASL) by exciting the Pacific–South America (PSA) atmospheric teleconnection, which significantly contributed to the negative phase of ADP during austral winter and spring. Similarly, during austral spring, the AMO’s transition from a negative to a positive phase during the same period further deepened the ASL by exciting a Rossby wave and PSA wave train across the South Pacific basin. This process reduced warm water by weakening Ekman suction, contributing to the negative ADP and increasing sea ice trend in the eastern Ross Sea, Amundsen Sea, and Indian Ocean. The AMO’s phase shift accounted for approximately 75% of the austral spring Antarctic SIE increase. 75% of the austral spring Antarctic SIE increase. During austral summer, the phase transitions of both the IPO and AMO may have strengthened the southern annular mode, further contributing to the increased trend of Antarctic sea ice. Our results suggest the seasonal and regional impacts of IPO and AMO phase shifts on Antarctic sea ice trends, mediated through atmospheric teleconnection mechanisms.