diff --git a/CHANGELOG.md b/CHANGELOG.md
index 8569a8b..96a810c 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -5,6 +5,15 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](https://semver.org/).
 
+## 3.0.3
+
+### Fixed
+
+- `EventbridgeClient.putEvents`: send the entry `Time` as a `Date` rather than an
+  ISO string. Under AWS SDK v3, `PutEventsCommand` rejects a string timestamp
+  with `SerializationException: STRING_VALUE can not be converted to milliseconds
+  since epoch`, so any event carrying a `time` failed since the v3 upgrade.
+
 ## 3.0.0
 
 ### Changed
diff --git a/lib/clients/eventbridge.js b/lib/clients/eventbridge.js
index 3a5ab5b..e56b919 100644
--- a/lib/clients/eventbridge.js
+++ b/lib/clients/eventbridge.js
@@ -110,7 +110,8 @@ const formatEventInput = (eventBusName) =>
     filter(reject(isNil)),
     evolve({
       detail: toJson,
-      time: compose(toIso, fromIsoUtc)
+      // SDK v3 PutEvents needs a real Date; an ISO string throws SerializationException.
+      time: compose((iso) => new Date(iso), toIso, fromIsoUtc)
     }),
     keysToPascalCase
   )
diff --git a/lib/clients/eventbridge.spec.js b/lib/clients/eventbridge.spec.js
index 5dbd69e..58073d3 100644
--- a/lib/clients/eventbridge.spec.js
+++ b/lib/clients/eventbridge.spec.js
@@ -142,7 +142,7 @@ const eventInput = [
 ]
 
 const eventEntry = {
-  Time: '2020-01-01T00:00:00.000Z',
+  Time: new Date('2020-01-01T00:00:00.000Z'),
   Source: 'mock-source',
   Resources: ['mock-resource'],
   DetailType: 'mock-detail-type',