diff --git a/core/src/Datarekisteri/Core/Types.hs b/core/src/Datarekisteri/Core/Types.hs
index bdd1af8..5d04874 100644
--- a/core/src/Datarekisteri/Core/Types.hs
+++ b/core/src/Datarekisteri/Core/Types.hs
@@ -101,7 +101,8 @@ renderPhoneNumber (PhoneNumber txt) = txt
 toPhoneNumber :: Text -> Maybe PhoneNumber
 toPhoneNumber txt = do
     guard $ not $ T.null txt
-    guard $ T.all (`elem` ("+ 0123456789" :: [Char])) txt
+    guard $ T.head txt `elem` ['+','0']
+    guard $ T.all (`elem` (" 0123456789" :: [Char])) $ T.tail txt
     pure $ PhoneNumber txt
 
 instance Eq PhoneNumber where
diff --git a/frontend/src/Datarekisteri/Frontend/FormFields.hs b/frontend/src/Datarekisteri/Frontend/FormFields.hs
index 7121fc1..af01973 100644
--- a/frontend/src/Datarekisteri/Frontend/FormFields.hs
+++ b/frontend/src/Datarekisteri/Frontend/FormFields.hs
@@ -39,7 +39,7 @@ telephoneField = Field
     , fieldView = \id name otherAttributes result isRequired ->
         let result' = either (\x -> x) renderPhoneNumber result
         in [whamlet|
-               <input type="tel" id="#{id}" name="#{name}" value="#{result'}" pattern="[+ 0123456789]*" title="Only '+', spaces and numbers are allowed" "*{otherAttributes} :isRequired:required="true">
+               <input type="tel" id="#{id}" name="#{name}" value="#{result'}" pattern="[+0][ 0123456789]*" title="Only '+', spaces and numbers are allowed" "*{otherAttributes} :isRequired:required="true">
            |]
     , fieldEnctype = UrlEncoded
     }