diff --git a/media_source/templates/administrator/atum/scss/_variables-dark.scss b/media_source/templates/administrator/atum/scss/_variables-dark.scss
index 12f7b58aec6fc..ad1393fbf413b 100644
--- a/media_source/templates/administrator/atum/scss/_variables-dark.scss
+++ b/media_source/templates/administrator/atum/scss/_variables-dark.scss
@@ -99,7 +99,7 @@ $atum-colors-dark: (
 
   form-check-input-checked-bg-image:      url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3e%3cpath fill='none' stroke='%23eee' stroke-linecap='round' stroke-linejoin='round' stroke-width='3' d='m6 10 3 3 6-6'/%3e%3c/svg%3e"),
   form-check-input-checked-bg-color:      $btn-primary-dark,
-  form-check-input-border:                1px solid rgba(255, 255, 255, .2), // rgba(255, 255, 255, .05),
+  form-check-input-border:                1px solid rgba(255, 255, 255, .5), // contrast ratio: 5.29 on #0f151d
 
   form-select-background:                 $form-select-bg-dark $form-select-indicator-dark no-repeat right center / $form-select-bg-size, // Used so we can have multiple background elements (e.g., arrow and feedback icon)
   form-select-background-rtl:             $form-select-bg-dark $form-select-indicator-rtl-dark no-repeat left center / $form-select-bg-size, // Used so we can have multiple background elements (e.g. arrow and feedback icon)
diff --git a/media_source/templates/administrator/atum/scss/_variables.scss b/media_source/templates/administrator/atum/scss/_variables.scss
index b4b272baf527c..eeab284918a77 100644
--- a/media_source/templates/administrator/atum/scss/_variables.scss
+++ b/media_source/templates/administrator/atum/scss/_variables.scss
@@ -155,7 +155,7 @@ $atum-colors: (
 
   form-check-input-checked-bg-image:       url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 20 20'%3e%3cpath fill='none' stroke='%23fff' stroke-linecap='round' stroke-linejoin='round' stroke-width='3' d='m6 10 3 3 6-6'/%3e%3c/svg%3e"),
   form-check-input-checked-bg-color:       $blue,
-  form-check-input-border:                 var(--border-width) solid var(--template-bg-dark-20),
+  form-check-input-border:                 var(--border-width) solid var(--template-bg-dark-60), // contrast ratio: 6.35 on #fff
 
   form-select-background:                  $form-select-bg $form-select-indicator no-repeat right center / $form-select-bg-size, // Used so we can have multiple background elements (e.g., arrow and feedback icon)
   form-select-background-rtl:              $form-select-bg $form-select-indicator-rtl no-repeat left center / $form-select-bg-size, // Used so we can have multiple background elements (e.g., arrow and feedback icon)
diff --git a/media_source/templates/administrator/atum/scss/blocks/_global.scss b/media_source/templates/administrator/atum/scss/blocks/_global.scss
index acbbb2d629eec..47cc83acd938b 100644
--- a/media_source/templates/administrator/atum/scss/blocks/_global.scss
+++ b/media_source/templates/administrator/atum/scss/blocks/_global.scss
@@ -40,6 +40,8 @@ body {
   }
 
   &.a11y_contrast {
+    --form-check-input-border: 2px solid var(--body-color);
+
     filter: contrast(115%);
   }
 
diff --git a/media_source/templates/site/cassiopeia/scss/tools/variables/_variables.scss b/media_source/templates/site/cassiopeia/scss/tools/variables/_variables.scss
index 8f7d9081bb9c7..daff380c2fe61 100644
--- a/media_source/templates/site/cassiopeia/scss/tools/variables/_variables.scss
+++ b/media_source/templates/site/cassiopeia/scss/tools/variables/_variables.scss
@@ -192,6 +192,7 @@ $table-variants: (
 
 // Forms
 $input-border-color:                  $gray-400 !default;
+$form-check-input-border:             var(--border-width) solid $gray-600 !default; // contrast ratio: 4.7 on #fff
 $input-padding:                       .6rem 1rem !default;
 $input-btn-padding-y:                 .6rem !default;
 $input-btn-padding-x:                 1rem !default;