diff --git a/packages/webapp/src/lib/stores/settings.test.ts b/packages/webapp/src/lib/stores/settings.test.ts
index 83df044525..885c41d737 100644
--- a/packages/webapp/src/lib/stores/settings.test.ts
+++ b/packages/webapp/src/lib/stores/settings.test.ts
@@ -58,6 +58,26 @@ describe('settings store', () => {
 			validChainIds.set([1, 42161]);
 			expect(get(selectedChainIds)).toEqual([1, 42161]);
 		});
+
+		it('seeds selectedChainIds with all validChainIds when selectedChainIds is empty', () => {
+			// Fresh user: no prior chain selection.
+			// When the client discovers which chains are available, select them all so
+			// orders are visible without requiring a wallet connection first.
+			validChainIds.set([1, 137, 42161]);
+
+			expect(get(selectedChainIds)).toEqual([1, 137, 42161]);
+		});
+
+		it('does not re-seed selectedChainIds when validChainIds updates and selectedChainIds is already set', () => {
+			// Returning user: their explicit selection must not be clobbered when
+			// validChainIds is refreshed (e.g. after a re-init).
+			selectedChainIds.set([1, 42161]);
+
+			validChainIds.set([1, 137, 42161]);
+
+			// 137 must NOT be auto-added; user chose 1 and 42161.
+			expect(get(selectedChainIds)).toEqual([1, 42161]);
+		});
 	});
 
 	describe('selectedChainIds localStorage persistence', () => {
diff --git a/packages/webapp/src/lib/stores/settings.ts b/packages/webapp/src/lib/stores/settings.ts
index 797eae42e2..6e34ed3136 100644
--- a/packages/webapp/src/lib/stores/settings.ts
+++ b/packages/webapp/src/lib/stores/settings.ts
@@ -66,6 +66,7 @@ export const validChainIds = writable<number[]>([]);
 validChainIds.subscribe((valid) => {
 	if (valid.length > 0) {
 		selectedChainIds.update((current) => {
+			if (current.length === 0) return [...valid];
 			const filtered = current.filter((id) => valid.includes(id));
 			return filtered.length !== current.length ? filtered : current;
 		});