diff --git a/CHANGES.md b/CHANGES.md
index 8b48294d4..0903a0a04 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,4 +1,4 @@
-# 3.1.0 -- 2024-??-??
+# 3.1.0 -- 2024-02-05
 
 ## Language changes
 
diff --git a/cryptol-remote-api/CHANGELOG.md b/cryptol-remote-api/CHANGELOG.md
index 543f43a60..241145640 100644
--- a/cryptol-remote-api/CHANGELOG.md
+++ b/cryptol-remote-api/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Revision history for `cryptol-remote-api` and `cryptol-eval-server`
 
-## 3.1.0 -- 2024-??-??
+## 3.1.0 -- 2024-02-05
 
 * The v3.1.0 release is made in tandem with the Cryptol 3.1.0 release. See the
   Cryptol 3.1.0 release notes for relevant Cryptol changes.
diff --git a/cryptol-remote-api/python/CHANGELOG.md b/cryptol-remote-api/python/CHANGELOG.md
index d09e58f48..fb1cf46c0 100644
--- a/cryptol-remote-api/python/CHANGELOG.md
+++ b/cryptol-remote-api/python/CHANGELOG.md
@@ -1,6 +1,6 @@
 # Revision history for `cryptol` Python package
 
-## 3.1.0 -- 2024-??-??
+## 3.1.0 -- 2024-02-05
 
 * The v3.1.0 release is made in tandem with the Cryptol 3.1.0 release. See the
   Cryptol 3.1.0 release notes for relevant Cryptol changes.