diff --git a/CMakeLists.txt b/CMakeLists.txt
index fbaf775..008bd55 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -68,6 +68,14 @@ else()
 	set(VERSION_GIT_FULL "${VERSION_GIT}-${VERSION_GIT_IS_DIRTY}")
 endif()
 
+# Download submodules if needed
+
+if(NOT EXISTS ${CMAKE_SOURCE_DIR}/src/configparser/.git OR NOT EXISTS ${CMAKE_SOURCE_DIR}/src/cppgtfs/.git OR NOT EXISTS ${CMAKE_SOURCE_DIR}/src/xml/.git)
+    execute_process(
+        COMMAND git submodule update --init --recursive
+    )
+endif()
+
 add_subdirectory(src)
 
 # tests