diff --git a/pkgs/development/tools/swiftpm2nix/support.nix b/pkgs/development/tools/swiftpm2nix/support.nix
index 9b944a133daa..dfc2d01a4501 100644
--- a/pkgs/development/tools/swiftpm2nix/support.nix
+++ b/pkgs/development/tools/swiftpm2nix/support.nix
@@ -29,6 +29,7 @@ in rec {
         url = dep.packageRef.location;
         rev = dep.state.checkoutState.revision;
         sha256 = hashes.${dep.subpath};
+        fetchSubmodules = true;
       })) workspaceState.object.dependencies
     );
 
diff --git a/pkgs/development/tools/swiftpm2nix/swiftpm2nix.sh b/pkgs/development/tools/swiftpm2nix/swiftpm2nix.sh
index db00b1ad2b52..eda7f475064a 100755
--- a/pkgs/development/tools/swiftpm2nix/swiftpm2nix.sh
+++ b/pkgs/development/tools/swiftpm2nix/swiftpm2nix.sh
@@ -23,7 +23,7 @@ hashes=""
 jq -r '.object.dependencies[] | "\(.subpath) \(.packageRef.location) \(.state.checkoutState.revision)"' $stateFile \
 | while read -r name url rev; do
   echo >&2 "-- Fetching $name"
-  sha256="$(nix-prefetch-git $url $rev | jq -r .sha256)"
+  sha256="$(nix-prefetch-git --fetch-submodules $url $rev | jq -r .sha256)"
   hashes+="
     \"$name\" = \"$sha256\";"
   echo >&2