diff --git a/CHANGELOG.md b/CHANGELOG.md
index ed69c327753..8e3e99d406b 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -43,6 +43,9 @@ release.
   ([#3390](https://github.com/open-telemetry/opentelemetry-specification/pull/3390))
 - BREAKING: Remove `messaging.consumer.id`, make `messaging.client_id` generic
   ([#3336](https://github.com/open-telemetry/opentelemetry-specification/pull/3336))
+- Add transition plan for upcoming breaking changes to the unstable HTTP semantic
+  conventions.
+  ([#3404](https://github.com/open-telemetry/opentelemetry-specification/pull/3404))
 
 ### Compatibility
 
diff --git a/specification/metrics/semantic_conventions/http-metrics.md b/specification/metrics/semantic_conventions/http-metrics.md
index 968b0575494..efe5fda957a 100644
--- a/specification/metrics/semantic_conventions/http-metrics.md
+++ b/specification/metrics/semantic_conventions/http-metrics.md
@@ -26,6 +26,21 @@ operations. By adding HTTP attributes to metric events it allows for finely tune
 
 <!-- tocstop -->
 
+> **Warning**
+> v1.21.0 of this document will introduce significant breaking changes to the (not yet stable)
+> HTTP semantic conventions.
+>
+> HTTP instrumentations updating from
+> [v1.20.0 of this document](https://github.com/open-telemetry/opentelemetry-specification/blob/v1.20.0/specification/metrics/semantic_conventions/http-metrics.md)
+> (or prior) to this new version SHOULD either:
+>
+> * wait to update until at least October 1, 2023, or
+> * bump their major version and wait to release a stable version of the new major
+>   version until at least October 1, 2023.
+>
+> In both cases, the minor version prior to the update SHOULD be supported until
+> February 1, 2024 (e.g. at least security patches).
+
 ## HTTP Server
 
 ### Metric: `http.server.duration`
diff --git a/specification/trace/semantic_conventions/http.md b/specification/trace/semantic_conventions/http.md
index dba45b01b57..4de980ceca5 100644
--- a/specification/trace/semantic_conventions/http.md
+++ b/specification/trace/semantic_conventions/http.md
@@ -27,6 +27,21 @@ and various HTTP versions like 1.1, 2 and SPDY.
 
 <!-- tocstop -->
 
+> **Warning**
+> v1.21.0 of this document will introduce significant breaking changes to the (not yet stable)
+> HTTP semantic conventions.
+>
+> HTTP instrumentations updating from
+> [v1.20.0 of this document](https://github.com/open-telemetry/opentelemetry-specification/blob/v1.20.0/specification/trace/semantic_conventions/http.md)
+> (or prior) to this new version SHOULD either:
+>
+> * wait to update until at least October 1, 2023, or
+> * bump their major version and wait to release a stable version of the new major
+>   version until at least October 1, 2023.
+>
+> In both cases, the minor version prior to the update SHOULD be supported until
+> February 1, 2024 (e.g. at least security patches).
+
 ## Name
 
 HTTP spans MUST follow the overall [guidelines for span names](../api.md#span).