diff --git a/crates/avian2d/Cargo.toml b/crates/avian2d/Cargo.toml
index e6e97a1a..0d21cb30 100644
--- a/crates/avian2d/Cargo.toml
+++ b/crates/avian2d/Cargo.toml
@@ -39,6 +39,7 @@ serialize = [
     "bevy/serialize",
     "parry2d?/serde-serialize",
     "parry2d-f64?/serde-serialize",
+    "bitflags/serde",
 ]
 
 [lib]
diff --git a/crates/avian3d/Cargo.toml b/crates/avian3d/Cargo.toml
index 81f9d961..b451f408 100644
--- a/crates/avian3d/Cargo.toml
+++ b/crates/avian3d/Cargo.toml
@@ -48,6 +48,7 @@ serialize = [
     "bevy/serialize",
     "parry3d?/serde-serialize",
     "parry3d-f64?/serde-serialize",
+    "bitflags/serde",
 ]
 
 [lib]