diff --git a/docshell/test/navigation/mochitest.ini b/docshell/test/navigation/mochitest.ini
index 660218d680cf..552d34f226de 100644
--- a/docshell/test/navigation/mochitest.ini
+++ b/docshell/test/navigation/mochitest.ini
@@ -58,6 +58,7 @@ support-files =
 
 [test_bug13871.html]
 fail-if = fission
+skip-if = fission && debug # Times out.
 [test_bug270414.html]
 fail-if = fission
 [test_bug278916.html]
@@ -77,7 +78,9 @@ fail-if = fission
 skip-if = fission && (debug || asan) # Causes shutdown leaks under Fission.
 [test_not-opener.html]
 fail-if = fission
+skip-if = fission && debug # Times out
 [test_opener.html]
+skip-if = fission && debug # Times out
 [test_popup-navigates-children.html]
 fail-if = fission
 [test_reserved.html]