The Siege of San Sebastian
July-September 1813 · The Fortress on the Northern Coast
The Siege of San Sebastian, from July to September 1813, removed the last major French fortress on the northern Spanish coast. After a failed first assault, British artillery breached the walls and the fortress fell on 31 August after bitter fighting. Its capture secured Allied supply lines and opened the way into the Pyrenees.
Background
The coastal fortress of San Sebastian remained in French hands despite the disaster at Vitoria.
The Siege
After an initial failed assault in July, British artillery created massive breaches during a second attempt. The final assault on 31 August succeeded after bitter fighting. As at Badajoz, discipline collapsed following the capture. Large parts of the town were destroyed by fire.
Significance
The fortress secured Allied supply lines along the northern coast and opened the way into the Pyrenees.
Where This Fits in the Peninsular War
The Siege of San Sebastian was fought during the turning point of the war (1812-1813). See where it sits in the full chronology of the campaign, from the first British landings in Portugal to the final battle at Toulouse, on the complete campaign guide.
Page last updated: July 2026