diff --git a/workspaces/src/network/sandbox.rs b/workspaces/src/network/sandbox.rs
index 1ac29fe4..fee4cfb1 100644
--- a/workspaces/src/network/sandbox.rs
+++ b/workspaces/src/network/sandbox.rs
@@ -182,6 +182,10 @@ impl RootAccountSubaccountCreator for Sandbox {
         subaccount_prefix: AccountId,
         sk: SecretKey,
     ) -> Result<Execution<Account>> {
+        if subaccount_prefix.as_str().contains('.') {
+            return Err(crate::error::ErrorKind::Io
+                .custom("Subaccount prefix for subaccount created cannot contain '.'"));
+        }
         let root_id = self.root_account_id()?;
         let id = AccountId::from_str(format!("{}.{}", subaccount_prefix, root_id).as_str())
             .map_err(|e| ErrorKind::DataConversion.custom(e))?;
@@ -203,6 +207,10 @@ impl RootAccountSubaccountCreator for Sandbox {
         sk: SecretKey,
         wasm: &[u8],
     ) -> Result<Execution<Contract>> {
+        if subaccount_prefix.as_str().contains('.') {
+            return Err(crate::error::ErrorKind::Io
+                .custom("Subaccount prefix for subaccount created cannot contain '.'"));
+        }
         let root_id = self.root_account_id()?;
         let id = AccountId::from_str(format!("{}.{}", subaccount_prefix, root_id).as_str())
             .map_err(|e| ErrorKind::DataConversion.custom(e))?;
diff --git a/workspaces/src/network/testnet.rs b/workspaces/src/network/testnet.rs
index 4de14bbb..c4d2272d 100644
--- a/workspaces/src/network/testnet.rs
+++ b/workspaces/src/network/testnet.rs
@@ -79,6 +79,10 @@ impl RootAccountSubaccountCreator for Testnet {
         sk: SecretKey,
         // TODO: return Account only, but then you don't get metadata info for it...
     ) -> Result<Execution<Account>> {
+        if subaccount_prefix.as_str().contains('.') {
+            return Err(crate::error::ErrorKind::Io
+                .custom("Subaccount prefix for subaccount created cannot contain '.'"));
+        }
         let url = Url::parse(HELPER_URL).unwrap();
         let root_id = self
             .root_account_id()
diff --git a/workspaces/src/network/variants.rs b/workspaces/src/network/variants.rs
index 902769fa..5478559e 100644
--- a/workspaces/src/network/variants.rs
+++ b/workspaces/src/network/variants.rs
@@ -22,7 +22,7 @@ pub trait NetworkInfo {
 /// For example, if this parameter is `"subaccount"` then
 /// the full ID for testnet will be `"subaccount.testnet"`.
 ///
-/// It is expected that the `subaccount_prefix` does not contain a `.`.
+/// Currently all implementations validate that `subaccount_prefix` does not contain a `.`.
 #[async_trait]
 pub trait RootAccountSubaccountCreator {
     /// for sandbox value of [`Worker::<Sandbox>::root_account`]
@@ -136,10 +136,6 @@ where
         subaccount_prefix: AccountId,
         sk: SecretKey,
     ) -> Result<Execution<Account>> {
-        if subaccount_prefix.as_str().contains('.') {
-            return Err(crate::error::ErrorKind::Io
-                .custom("Subaccount prefix for subaccount created cannot contain '.'"));
-        }
         let res = self
             .workspace
             .create_root_account_subaccount(self.clone().coerce(), subaccount_prefix, sk)
@@ -158,10 +154,6 @@ where
         sk: SecretKey,
         wasm: &[u8],
     ) -> Result<Execution<Contract>> {
-        if subaccount_prefix.as_str().contains('.') {
-            return Err(crate::error::ErrorKind::Io
-                .custom("Subaccount prefix for subaccount created cannot contain '.'"));
-        }
         let res = self
             .workspace
             .create_root_account_subaccount_and_deploy(