diff --git a/test/SerialIOTest.cpp b/test/SerialIOTest.cpp
index 5bac468525..c0103acebc 100644
--- a/test/SerialIOTest.cpp
+++ b/test/SerialIOTest.cpp
@@ -81,7 +81,10 @@ std::vector<std::string> testedFileExtensions()
         allExtensions.begin(), allExtensions.end(), [](std::string const &ext) {
             // sst and ssc need a receiver for testing
             // bp4 is already tested via bp
-            return ext == "sst" || ext == "ssc" || ext == "bp4";
+            // toml parsing is very slow and its implementation is equivalent to
+            // the json backend, so it is only activated for selected tests
+            return ext == "sst" || ext == "ssc" || ext == "bp4" ||
+                ext == "toml";
         });
     return {allExtensions.begin(), newEnd};
 }
@@ -1590,6 +1593,11 @@ TEST_CASE("dtype_test", "[serial]")
     {
         dtype_test(t);
     }
+    /*
+     * TOML backend is not generally tested for performance reasons, opt in to
+     * testing it here.
+     */
+    dtype_test("toml");
 }
 
 inline void write_test(const std::string &backend)
@@ -2188,6 +2196,11 @@ TEST_CASE("fileBased_write_test", "[serial]")
     {
         fileBased_write_test(t);
     }
+    /*
+     * TOML backend is not generally tested for performance reasons, opt in to
+     * testing it here.
+     */
+    fileBased_write_test("toml");
 }
 
 inline void sample_write_thetaMode(std::string file_ending)
@@ -7238,4 +7251,9 @@ TEST_CASE("groupbased_read_write", "[serial]")
             }
         }
     }
+    /*
+     * TOML backend is not generally tested for performance reasons, opt in to
+     * testing it here.
+     */
+    groupbased_read_write("toml");
 }