diff --git a/changelog/change_preset_ruby_stdlib_api_for_variable_number.md b/changelog/change_preset_ruby_stdlib_api_for_variable_number.md
new file mode 100644
index 000000000000..9656776172d1
--- /dev/null
+++ b/changelog/change_preset_ruby_stdlib_api_for_variable_number.md
@@ -0,0 +1 @@
+* [#9104](https://github.com/rubocop-hq/rubocop/issues/9104): Preset some stdlib method names for `Naming/VariableNumber`. ([@koic][])
diff --git a/config/default.yml b/config/default.yml
index 87a43b876cbf..a4aef5e69da8 100644
--- a/config/default.yml
+++ b/config/default.yml
@@ -2466,7 +2466,13 @@ Naming/VariableNumber:
     - non_integer
   CheckMethodNames: true
   CheckSymbols: true
-  AllowedIdentifiers: []
+  AllowedIdentifiers:
+    - capture3     # Open3.capture3
+    - iso8601      # Time#iso8601
+    - rfc1123_date # CGI.rfc1123_date
+    - rfc822       # Time#rfc822
+    - rfc2822      # Time#rfc2822
+    - rfc3339      # DateTime.rfc3339
 
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