diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000000..2f391c0d6a
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,6 @@
+[submodule "rte-rrtmgp"]
+	path = src/physics/rrtmgp/ext
+	url = https://github.com/earth-system-radiation/rte-rrtmgp.git
+[submodule "rrtmgp-data"]
+	path = src/physics/rrtmgp/data
+	url = https://github.com/earth-system-radiation/rrtmgp-data.git
diff --git a/Externals_CAM.cfg b/Externals_CAM.cfg
index debf4c613e..5ff4cdb908 100644
--- a/Externals_CAM.cfg
+++ b/Externals_CAM.cfg
@@ -87,17 +87,13 @@ required = True
 externals = Externals_HCO.cfg
 
 [rte-rrtmgp]
-local_path = src/physics/rrtmgp/ext
 protocol = git
-repo_url = https://github.com/earth-system-radiation/rte-rrtmgp.git
-tag = v1.7
+from_submodule = True
 required = True
 
 [rrtmgp-data]
-local_path = src/physics/rrtmgp/data
 protocol = git
-repo_url = https://github.com/earth-system-radiation/rrtmgp-data.git
-tag = v1.8
+from_submodule = True
 required = True
 
 [externals_description]
diff --git a/src/physics/rrtmgp/data b/src/physics/rrtmgp/data
new file mode 160000
index 0000000000..df02975ab9
--- /dev/null
+++ b/src/physics/rrtmgp/data
@@ -0,0 +1 @@
+Subproject commit df02975ab93165b34a59f0d04b4ae6148fe5127c
diff --git a/src/physics/rrtmgp/ext b/src/physics/rrtmgp/ext
new file mode 160000
index 0000000000..1e087216d3
--- /dev/null
+++ b/src/physics/rrtmgp/ext
@@ -0,0 +1 @@
+Subproject commit 1e087216d3d31f608e33b17491e2334ede8c5d5a