diff --git a/.gitmodules b/.gitmodules
index fed3de512..cddc791b0 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -1,3 +1,6 @@
 [submodule "src/libshared"]
 	path = src/libshared
 	url = https://github.com/GothenburgBitFactory/libshared.git
+[submodule "src/tc/corrosion"]
+	path = src/tc/corrosion
+	url = https://github.com/corrosion-rs/corrosion.git
diff --git a/src/tc/CMakeLists.txt b/src/tc/CMakeLists.txt
index 500ad1727..165af059c 100644
--- a/src/tc/CMakeLists.txt
+++ b/src/tc/CMakeLists.txt
@@ -1,11 +1,6 @@
 cmake_minimum_required (VERSION 3.22)
 
-FetchContent_Declare (
-    Corrosion
-    GIT_REPOSITORY https://github.com/corrosion-rs/corrosion.git
-    GIT_TAG v0.4.7
-)
-FetchContent_MakeAvailable(Corrosion)
+add_subdirectory(${CMAKE_SOURCE_DIR}/src/tc/corrosion)
 
 # Import taskchampion-lib as a CMake library.
 corrosion_import_crate(
diff --git a/src/tc/corrosion b/src/tc/corrosion
new file mode 160000
index 000000000..8ddd6d56c
--- /dev/null
+++ b/src/tc/corrosion
@@ -0,0 +1 @@
+Subproject commit 8ddd6d56ca597cb855f532e9ba4c7bc1cbe0803b