diff --git a/admin/tool/customlang/tests/behat/customisation_create.feature b/admin/tool/customlang/tests/behat/customisation_create.feature
index 84f71bb8ba9..1d139473593 100644
--- a/admin/tool/customlang/tests/behat/customisation_create.feature
+++ b/admin/tool/customlang/tests/behat/customisation_create.feature
@@ -5,7 +5,10 @@ Feature: Within a moodle instance, an administrator should be able to modify lan
   I need to be able to access and change values in the the language customisation of the language pack.
 
   Background:
-    Given I log in as "admin"
+    # This is a very slow running test and on slow databases can take minutes to complete.
+    Given I mark this test as slow setting a timeout factor of 4
+
+    And I log in as "admin"
     And I navigate to "Language > Language customisation" in site administration
     And I set the field "lng" to "en"
     And I press "Open language pack for editing"
diff --git a/admin/tool/customlang/tests/behat/export.feature b/admin/tool/customlang/tests/behat/export.feature
index a42e6722b08..8ff826d5b30 100644
--- a/admin/tool/customlang/tests/behat/export.feature
+++ b/admin/tool/customlang/tests/behat/export.feature
@@ -4,6 +4,10 @@ Feature: Within a moodle instance, an administrator should be able to export mod
   As an admin
   I need to be able to export the php-files of the language customisation of a language.
 
+  Background:
+    # This is a very slow running feature and on slow databases can take minutes to complete.
+    Given I mark this test as slow setting a timeout factor of 4
+
   @javascript
   Scenario: Export button should not appear if no customization is made
     Given I log in as "admin"
diff --git a/admin/tool/customlang/tests/behat/import_files.feature b/admin/tool/customlang/tests/behat/import_files.feature
index 20df1c0f675..3d93dfec90f 100644
--- a/admin/tool/customlang/tests/behat/import_files.feature
+++ b/admin/tool/customlang/tests/behat/import_files.feature
@@ -5,7 +5,10 @@ Feature: Within a moodle instance, an administrator should be able to import mod
   I need to be able to import the zips and php files of the language customisation of a language.
 
   Background:
-    Given I log in as "admin"
+    # This is a very slow running test and on slow databases can take minutes to complete.
+    Given I mark this test as slow setting a timeout factor of 4
+
+    And I log in as "admin"
     And I navigate to "Language > Language customisation" in site administration
     And I set the field "lng" to "en"
     And I click on "Import custom strings" "button"
diff --git a/admin/tool/customlang/tests/behat/import_mode.feature b/admin/tool/customlang/tests/behat/import_mode.feature
index 2347cf24e9d..e977237a5e8 100644
--- a/admin/tool/customlang/tests/behat/import_mode.feature
+++ b/admin/tool/customlang/tests/behat/import_mode.feature
@@ -5,8 +5,11 @@ Feature: Within a moodle instance, an administrator should be able to import lan
   I need to be able to import only some language customisation strings depending on some conditions.
 
   Background:
+    # This is a very slow running feature and on slow databases can take minutes to complete.
+    Given I mark this test as slow setting a timeout factor of 4
+
     # Add one customization.
-    Given I log in as "admin"
+    And I log in as "admin"
     And I navigate to "Language > Language customisation" in site administration
     And I set the field "lng" to "en"
     And I press "Open language pack for editing"
diff --git a/admin/tool/httpsreplace/tests/behat/httpsreplace.feature b/admin/tool/httpsreplace/tests/behat/httpsreplace.feature
index 76e77e0f8f7..f8d99f95059 100644
--- a/admin/tool/httpsreplace/tests/behat/httpsreplace.feature
+++ b/admin/tool/httpsreplace/tests/behat/httpsreplace.feature
@@ -5,7 +5,10 @@ Feature: View the httpsreplace report
   I need to be able to automatically replace http links
 
   Background: Create some http links
-    Given I am on site homepage
+    # This is a slow running feature and on slow databases can take over 30 seconds to complete.
+    Given I mark this test as slow setting a timeout factor of 2
+
+    And I am on site homepage
     And the following "courses" exist:
       | fullname | shortname | category | summary                                                                                                     |
       | Course 1 | C1        | 0        | <img src="http://intentionally.unavailable/test.png"> <img src="http://download.moodle.org/unittest/test.jpg"> |