diff --git a/.chronus/changes/alternate-type-rust-2026-1-19-23-51-30.md b/.chronus/changes/alternate-type-rust-2026-1-19-23-51-30.md
new file mode 100644
index 0000000000..970e8908c4
--- /dev/null
+++ b/.chronus/changes/alternate-type-rust-2026-1-19-23-51-30.md
@@ -0,0 +1,8 @@
+---
+# Change versionKind to one of: internal, fix, dependencies, feature, deprecation, breaking
+changeKind: fix
+packages:
+  - "@azure-tools/azure-http-specs"
+---
+
+Update the `azure/client-generator-core/alternate-type` spec for Rust.
diff --git a/packages/azure-http-specs/specs/azure/client-generator-core/alternate-type/client.tsp b/packages/azure-http-specs/specs/azure/client-generator-core/alternate-type/client.tsp
index 737b57f8f0..a3b42ddbdd 100644
--- a/packages/azure-http-specs/specs/azure/client-generator-core/alternate-type/client.tsp
+++ b/packages/azure-http-specs/specs/azure/client-generator-core/alternate-type/client.tsp
@@ -43,3 +43,22 @@ using Azure.ClientGenerator.Core;
   },
   "typescript"
 );
+
+@@alternateType(_Specs_.Azure.ClientGenerator.Core.AlternateType.ExternalType.Feature,
+  {
+    identity: "geojson::Feature",
+    package: "geojson",
+    minVersion: "0.24.2",
+  },
+  "rust"
+);
+
+// When https://github.com/microsoft/typespec/issues/9749 is fixed, the statement below is no longer needed.
+@@alternateType(_Specs_.Azure.ClientGenerator.Core.AlternateType.ExternalType.Geometry,
+  {
+    identity: "geojson::Geometry",
+    package: "geojson",
+    minVersion: "0.24.2",
+  },
+  "rust"
+);