diff --git a/frontend/src/routes/guest/register/steps/register.test.tsx b/frontend/src/routes/guest/register/steps/register.test.tsx
index 087e7c5ac41fd9c116d0aecc19971a19324703a2..b5ac1b52e836b8574fe740772a63f2e044ab0567 100644
--- a/frontend/src/routes/guest/register/steps/register.test.tsx
+++ b/frontend/src/routes/guest/register/steps/register.test.tsx
@@ -392,3 +392,63 @@ test('Guest allowed to proceed in wizard if data is valid', async () => {
 
   expect(nextHandler.mock.calls.length).toBe(1)
 })
+
+test('Default country code gets set in form values', async () => {
+  // This stores the data sent from the form when the user clicks submit
+  let guestRegisterData: GuestRegisterData | null = null
+  const nextHandler = (registerData: GuestRegisterData) => {
+    guestRegisterData = registerData
+
+  }
+
+  const allFeaturesOn = {
+    displayContactAtUnit: true,
+    displayComment: true,
+    displayContactAtUnitGuestInput: true,
+    showGenderFieldForGuest: true,
+  }
+
+  // Leave the mobile phone country code blank, it should
+  // be populated with a default value
+  const formData: GuestRegisterData = {
+    firstName: 'Test',
+    lastName: 'Test2',
+    mobilePhoneCountry: '',
+    mobilePhone: '97543992',
+    nationalIdNumber: '',
+    passportNumber: '12345678',
+    passportNationality: 'NO',
+    dateOfBirth: addYears(-20)(new Date()),
+    gender: 'male',
+  }
+
+  const testData = getEmptyGuestData()
+  testData.gender = 'male'
+  const submitMock = jest.fn()
+
+  // Need this to be able to call on the submit-method on the form
+  const reference = {
+    current: {
+      doSubmit: submitMock,
+    },
+  }
+
+  render(
+    <FeatureContext.Provider value={allFeaturesOn}>
+      <LocalizationProvider dateAdapter={AdapterDateFns}>
+        <GuestRegisterStep
+          nextHandler={nextHandler}
+          initialGuestData={testData}
+          registerData={formData}
+          ref={reference}
+        />
+      </LocalizationProvider>
+    </FeatureContext.Provider>,
+  )
+
+  expect(guestRegisterData).toBeNull()
+  await act(async () => reference.current?.doSubmit())
+  // Check that the mobile country has gotten the default value
+  // @ts-ignore
+  expect(guestRegisterData.mobilePhoneCountry).toEqual('NO')
+})