diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6f01255480f..df16cbc3f5b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -149,6 +149,8 @@ instead.
     deprecated.
   - [`@Deprecated.instantiate()`][] indicates the ability to instantiate a
     class is deprecated.
+- The ability to implement the RegExp class and the RegExpMatch class is
+  deprecated.
 
 [#61392]: https://dartbug.com/61392
 [`@Deprecated.extend()`]: https://api.dart.dev/dev/latest/dart-core/Deprecated/Deprecated.extend.html
diff --git a/sdk/lib/core/regexp.dart b/sdk/lib/core/regexp.dart
index 048f6215784..6b10339292b 100644
--- a/sdk/lib/core/regexp.dart
+++ b/sdk/lib/core/regexp.dart
@@ -213,6 +213,10 @@ part of "dart:core";
 /// when the regexp does not find a match.
 /// Several guides to [improving the performance of regular expressions](https://www.google.com/search?q=performance+of+regular+expressions)
 /// exist on the internet. Use these as inspirations, too.
+@Deprecated.implement(
+  "This class will become 'final' in a future release. "
+  "'Pattern' may be a more appropriate interface to implement.",
+)
 abstract interface class RegExp implements Pattern {
   /// Constructs a regular expression.
   ///
@@ -468,6 +472,10 @@ abstract interface class RegExp implements Pattern {
 ///   // This is the second message.
 /// }
 /// ```
+@Deprecated.implement(
+  "This class will become 'final' in a future release."
+  "'Match' may be a more appropriate interface to implement.",
+)
 abstract interface class RegExpMatch implements Match {
   /// The string captured by the named capture group [name].
   ///