diff --git a/daml-assistant/daml-helper/src/DA/Daml/Helper/Main.hs b/daml-assistant/daml-helper/src/DA/Daml/Helper/Main.hs
index da86a41a3c..8018965c50 100644
--- a/daml-assistant/daml-helper/src/DA/Daml/Helper/Main.hs
+++ b/daml-assistant/daml-helper/src/DA/Daml/Helper/Main.hs
@@ -440,10 +440,10 @@ commandParser = subparser $ fold
 
     cantonSandboxCmd = do
         cantonOptions <- do
-            cantonLedgerApi <- option auto (long "port" <> value 6865)
-            cantonAdminApi <- option auto (long "admin-api-port" <> value 6866)
-            cantonDomainPublicApi <- option auto (long "domain-public-port" <> value 6867)
-            cantonDomainAdminApi <- option auto (long "domain-admin-port" <> value 6868)
+            cantonLedgerApi <- option auto (long "port" <> value (ledger defaultSandboxPorts))
+            cantonAdminApi <- option auto (long "admin-api-port" <> value (admin defaultSandboxPorts))
+            cantonDomainPublicApi <- option auto (long "domain-public-port" <> value (domainPublic defaultSandboxPorts))
+            cantonDomainAdminApi <- option auto (long "domain-admin-port" <> value (domainAdmin defaultSandboxPorts))
             cantonPortFileM <- optional $ option str (long "canton-port-file" <> metavar "PATH"
                 <> help "File to write canton participant ports when ready")
             cantonStaticTime <- StaticTime <$>
diff --git a/daml-assistant/daml-helper/src/DA/Daml/Helper/Start.hs b/daml-assistant/daml-helper/src/DA/Daml/Helper/Start.hs
index 5f88e04ffe..7d51891405 100644
--- a/daml-assistant/daml-helper/src/DA/Daml/Helper/Start.hs
+++ b/daml-assistant/daml-helper/src/DA/Daml/Helper/Start.hs
@@ -68,10 +68,10 @@ getPortForSandbox defaultPortSpec portSpecM =
 
 determineCantonOptions :: Maybe SandboxPortSpec -> SandboxCantonPortSpec -> FilePath -> IO CantonOptions
 determineCantonOptions ledgerApiSpec SandboxCantonPortSpec{..} portFile = do
-    cantonLedgerApi <- getPortForSandbox (SpecifiedPort (SandboxPort 6865)) ledgerApiSpec
-    cantonAdminApi <- getPortForSandbox FreePort adminApiSpec
-    cantonDomainPublicApi <- getPortForSandbox FreePort domainPublicApiSpec
-    cantonDomainAdminApi <- getPortForSandbox FreePort domainAdminApiSpec
+    cantonLedgerApi <- getPortForSandbox (SpecifiedPort (SandboxPort (ledger defaultSandboxPorts))) ledgerApiSpec
+    cantonAdminApi <- getPortForSandbox (SpecifiedPort (SandboxPort (admin defaultSandboxPorts))) adminApiSpec
+    cantonDomainPublicApi <- getPortForSandbox (SpecifiedPort (SandboxPort (domainPublic defaultSandboxPorts))) domainPublicApiSpec
+    cantonDomainAdminApi <- getPortForSandbox (SpecifiedPort (SandboxPort (domainAdmin defaultSandboxPorts))) domainAdminApiSpec
     let cantonPortFileM = Just portFile -- TODO allow canton port file to be passed in from command line?
     let cantonStaticTime = StaticTime False
     let cantonHelp = False
diff --git a/daml-assistant/daml-helper/src/DA/Daml/Helper/Util.hs b/daml-assistant/daml-helper/src/DA/Daml/Helper/Util.hs
index 27a664c3f4..d8783c2207 100644
--- a/daml-assistant/daml-helper/src/DA/Daml/Helper/Util.hs
+++ b/daml-assistant/daml-helper/src/DA/Daml/Helper/Util.hs
@@ -25,6 +25,8 @@ module DA.Daml.Helper.Util
   , waitForHttpServer
   , tokenFor
   , StaticTime(..)
+  , SandboxPorts(..)
+  , defaultSandboxPorts
   , CantonOptions(..)
   , decodeCantonSandboxPort
   , CantonReplApi(..)
@@ -250,6 +252,16 @@ tokenFor parties ledgerId applicationId =
             ]
       }
 
+data SandboxPorts = SandboxPorts
+  { ledger :: Int
+  , admin :: Int
+  , domainPublic :: Int
+  , domainAdmin :: Int
+  }
+
+defaultSandboxPorts :: SandboxPorts
+defaultSandboxPorts = SandboxPorts 6865 6866 6867 6868
+
 runCantonSandbox :: CantonOptions -> [String] -> IO ()
 runCantonSandbox options args = withCantonSandbox options args (const $ pure ())