diff --git a/src/tools/wasm-split/split-options.cpp b/src/tools/wasm-split/split-options.cpp
index cada7930b2e..b3c410cc534 100644
--- a/src/tools/wasm-split/split-options.cpp
+++ b/src/tools/wasm-split/split-options.cpp
@@ -231,7 +231,7 @@ WasmSplitOptions::WasmSplitOptions()
          "module into the secondary module. In instrument mode, refers to the "
          "namespace from which to import the secondary memory, if any.",
          WasmSplitOption,
-         {Mode::Split, Mode::Instrument},
+         {Mode::Split, Mode::MultiSplit, Mode::Instrument},
          Options::Arguments::One,
          [&](Options* o, const std::string& argument) {
            importNamespace = argument;
diff --git a/src/tools/wasm-split/wasm-split.cpp b/src/tools/wasm-split/wasm-split.cpp
index d26f6f1d63a..52966adede5 100644
--- a/src/tools/wasm-split/wasm-split.cpp
+++ b/src/tools/wasm-split/wasm-split.cpp
@@ -416,7 +416,7 @@ void multiSplitModule(const WasmSplitOptions& options) {
 
   ModuleSplitting::Config config;
   config.usePlaceholders = false;
-  config.importNamespace = "";
+  config.importNamespace = options.importNamespace;
   config.minimizeNewExportNames = true;
   for (auto& [mod, funcs] : moduleFuncs) {
     if (options.verbose) {