diff --git a/packages/seedless-onboarding-controller/CHANGELOG.md b/packages/seedless-onboarding-controller/CHANGELOG.md
index a991b2ac4a..9dcb4b2a63 100644
--- a/packages/seedless-onboarding-controller/CHANGELOG.md
+++ b/packages/seedless-onboarding-controller/CHANGELOG.md
@@ -12,6 +12,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Bump `@metamask/utils` from `^11.9.0` to `^11.11.0` ([#9074](https://github.com/MetaMask/core/pull/9074))
 - Bump `@metamask/keyring-controller` from `^27.0.0` to `^27.1.0` ([#9129](https://github.com/MetaMask/core/pull/9129))
 
+### Fixed
+
+- Fix `InvalidPrimarySecretDataType` thrown for legacy accounts where client clock skew sorts a non-mnemonic item ahead of the primary SRP ([#9247](https://github.com/MetaMask/core/pull/9247))
+
 ## [10.0.2]
 
 ### Changed
diff --git a/packages/seedless-onboarding-controller/src/SeedlessOnboardingController.test.ts b/packages/seedless-onboarding-controller/src/SeedlessOnboardingController.test.ts
index bc1406e3e6..542cf5ae91 100644
--- a/packages/seedless-onboarding-controller/src/SeedlessOnboardingController.test.ts
+++ b/packages/seedless-onboarding-controller/src/SeedlessOnboardingController.test.ts
@@ -3472,6 +3472,58 @@ describe('SeedlessOnboardingController', () => {
         },
       );
     });
+
+    it('should promote the primary SRP to first when a legacy non-mnemonic sorts ahead of it (clock skew)', async () => {
+      await withController(
+        {
+          state: getMockInitialControllerState({
+            withMockAuthenticatedUser: true,
+          }),
+        },
+        async ({ controller, toprfClient }) => {
+          mockRecoverEncKey(toprfClient, MOCK_PASSWORD);
+
+          // Legacy data (no dataType, no createdAt). An imported private key
+          // has the earliest client timestamp (e.g. due to clock skew on the
+          // device that imported it), so it sorts ahead of the primary SRP.
+          // The fetch must still recover by promoting the primary SRP, not
+          // throw InvalidPrimarySecretDataType.
+          const mockSecretDataGet = handleMockSecretDataGet({
+            status: 200,
+            body: createMockSecretDataGetResponse(
+              [
+                {
+                  data: new Uint8Array(Buffer.from('importedPk', 'utf-8')),
+                  timestamp: 100,
+                  type: SecretType.PrivateKey,
+                  itemId: 'imported-pk-id',
+                  // No dataType or createdAt (legacy)
+                },
+                {
+                  data: new Uint8Array(Buffer.from('primarySrp', 'utf-8')),
+                  timestamp: 200,
+                  type: SecretType.Mnemonic,
+                  itemId: 'primary-srp-id',
+                  // No dataType or createdAt (legacy)
+                },
+              ],
+              MOCK_PASSWORD,
+            ),
+          });
+
+          const secretData = await controller.fetchAllSecretData(MOCK_PASSWORD);
+
+          expect(mockSecretDataGet.isDone()).toBe(true);
+          expect(secretData).toHaveLength(2);
+          // Primary SRP (mnemonic) promoted to first despite later timestamp.
+          expect(secretData[0].type).toBe(SecretType.Mnemonic);
+          expect(secretData[0].data).toStrictEqual(stringToBytes('primarySrp'));
+          // The private key is preserved, not dropped.
+          expect(secretData[1].type).toBe(SecretType.PrivateKey);
+          expect(secretData[1].data).toStrictEqual(stringToBytes('importedPk'));
+        },
+      );
+    });
   });
 
   describe('submitPassword', () => {
diff --git a/packages/seedless-onboarding-controller/src/SeedlessOnboardingController.ts b/packages/seedless-onboarding-controller/src/SeedlessOnboardingController.ts
index 91020b33f2..6ec7f2e203 100644
--- a/packages/seedless-onboarding-controller/src/SeedlessOnboardingController.ts
+++ b/packages/seedless-onboarding-controller/src/SeedlessOnboardingController.ts
@@ -1646,22 +1646,38 @@ export class SeedlessOnboardingController<
       // Sort: PrimarySrp first, then by createdAt/timestamp (oldest first)
       results.sort((a, b) => SecretMetadata.compare(a, b, 'asc'));
 
-      // Validate the first item is the primary SRP
-      const firstItem = results[0];
-      const isDataTypePrimary =
-        firstItem.dataType === undefined ||
-        firstItem.dataType === null ||
-        firstItem.dataType === EncAccountDataType.PrimarySrp;
-      const isMnemonic = SecretMetadata.matchesType(
-        firstItem,
-        SecretType.Mnemonic,
-      );
+      // Find the primary SRP instead of assuming it is at index 0: legacy
+      // items have no `createdAt`, so ordering falls back to the client
+      // `timestamp`, which clock skew can sort a private key ahead of.
+      // A candidate is a mnemonic whose `dataType` is `PrimarySrp` or unset.
+      // `dataType` (a plaintext server field) is the only thing separating
+      // primary from imported SRP; legacy items lack it and the encrypted
+      // `SecretType` groups both, so among legacy mnemonics the primary is
+      // indistinguishable — we take the oldest (best-effort).
+      const primaryIndex = results.findIndex((item) => {
+        const isDataTypePrimary =
+          item.dataType === undefined ||
+          item.dataType === null ||
+          item.dataType === EncAccountDataType.PrimarySrp;
+        return (
+          isDataTypePrimary &&
+          SecretMetadata.matchesType(item, SecretType.Mnemonic)
+        );
+      });
 
-      if (!isDataTypePrimary || !isMnemonic) {
+      // No recoverable primary SRP exists in the metadata store.
+      if (primaryIndex === -1) {
         throw new Error(
           SeedlessOnboardingControllerErrorMessage.InvalidPrimarySecretDataType,
         );
       }
+
+      // Ensure the primary SRP is first; callers rely on `results[0]` being it.
+      if (primaryIndex > 0) {
+        const [primary] = results.splice(primaryIndex, 1);
+        results.unshift(primary);
+      }
+
       return results;
     }