The disintegration of the eastern Antarctic Peninsula’s Larsen A and B ice shelves has been attributed to regional-scale atmosphere and ocean warming, and increased mass-losses from the glaciers once restrained by these ice shelves have increased Antarctica’s total contribution to sea-level rise. Abrupt recessions in ice-shelf frontal position presaged the break-up of Larsen A and B, yet, in the ~20 years since these events, documented knowledge of frontal change along the entire ~1,400 km-long eastern Antarctic Peninsula is limited. Here, we show that 85% of the seaward ice-shelf perimeter fringing this coastline underwent uninterrupted advance between the early 2000s and 2019, in contrast to the two previous decades. These observations are derived from a detailed synthesis of historical (including DMSP OLS, ERS-1/2, Landsat 1-7, ENVISAT) and new, high temporal repeat-pass (Landsat 8, Sentinel-1a/b, Sentinel-2a/b) satellite records. By comparing our observations with a suite of state-of-the-art ocean reanalysis products, we attribute this advance to enhanced ocean-wave dampening, ice-shelf buttressing and the absence of sea-surface slope-induced ice-shelf flow, all of which were enabled by increased near-shore sea ice driven by a Weddell Sea-wide intensification of cyclonic near-surface winds since c. 2002. Collectively, our observations demonstrate that sea-ice change can either safeguard from, or set in motion, the final rifting and calving of even large Antarctic ice shelves.