diff --git a/docs/RELEASE-NOTES.md b/docs/RELEASE-NOTES.md
index 0c83840..129ce8f 100644
--- a/docs/RELEASE-NOTES.md
+++ b/docs/RELEASE-NOTES.md
@@ -8,6 +8,7 @@
 
 ### 수정
 - 지도: S57EncOverlay API URL을 공유 API_BASE_URL로 통합
+- 지도: S57 ENC sprite URL에 상대경로일 때 origin 프리픽스 추가
 
 ## [2026-03-31]
 
diff --git a/frontend/src/common/components/map/S57EncOverlay.tsx b/frontend/src/common/components/map/S57EncOverlay.tsx
index 9211754..4384d45 100644
--- a/frontend/src/common/components/map/S57EncOverlay.tsx
+++ b/frontend/src/common/components/map/S57EncOverlay.tsx
@@ -158,7 +158,10 @@ export function S57EncOverlay({ visible }: S57EncOverlayProps) {
 
       // sprite 등록 (중복 방지)
       if (!hasSprite(map, ENC_SPRITE_ID)) {
-        map.addSprite(ENC_SPRITE_ID, `${PROXY_PREFIX}/sprite/sprite`);
+        const spriteUrl = PROXY_PREFIX.startsWith('http')
+          ? `${PROXY_PREFIX}/sprite/sprite`
+          : `${window.location.origin}${PROXY_PREFIX}/sprite/sprite`;
+        map.addSprite(ENC_SPRITE_ID, spriteUrl);
       }
 
       // sources 등록 (타일 URL을 프록시로 치환)