diff --git a/.circleci/cmake-asan b/.circleci/cmake-asan
index 235bb9a8..49220cbe 100755
--- a/.circleci/cmake-asan
+++ b/.circleci/cmake-asan
@@ -6,6 +6,7 @@ CACHEDIR="$HOME/cache"
 
 . ".travis/flags-$CC.sh"
 add_flag -Werror
+add_flag -fdiagnostics-color=always
 add_flag -fsanitize=address
 cmake -B_build -H. -GNinja			\
   -DCMAKE_C_FLAGS="$C_FLAGS"			\
diff --git a/.circleci/cmake-tsan b/.circleci/cmake-tsan
index 60c2b515..65ccc437 100755
--- a/.circleci/cmake-tsan
+++ b/.circleci/cmake-tsan
@@ -6,6 +6,7 @@ CACHEDIR="$HOME/cache"
 
 . ".travis/flags-$CC.sh"
 add_flag -Werror
+add_flag -fdiagnostics-color=always
 add_flag -fsanitize=thread
 cmake -H. -B_build -GNinja			\
   -DCMAKE_C_FLAGS="$C_FLAGS"			\