diff --git a/modules/kms-keyring-browser/src/kms_keyring_browser.ts b/modules/kms-keyring-browser/src/kms_keyring_browser.ts
index a80f6d3e9..f5e2faeef 100644
--- a/modules/kms-keyring-browser/src/kms_keyring_browser.ts
+++ b/modules/kms-keyring-browser/src/kms_keyring_browser.ts
@@ -36,7 +36,7 @@ import {
 } from '@aws-crypto/material-management-browser'
 import { KMS } from 'aws-sdk' // eslint-disable-line no-unused-vars
 
-const getKmsClient = getClient(KMS)
+const getKmsClient = getClient(KMS, { customUserAgent: 'AwsEncryptionSdkJavascriptBrowser' })
 const cacheKmsClients = cacheClients(getKmsClient)
 
 export type KmsKeyringWebCryptoInput = Partial<KmsKeyringInput<KMS>>
diff --git a/modules/kms-keyring-node/src/kms_keyring_node.ts b/modules/kms-keyring-node/src/kms_keyring_node.ts
index 8db5e097c..328753ebb 100644
--- a/modules/kms-keyring-node/src/kms_keyring_node.ts
+++ b/modules/kms-keyring-node/src/kms_keyring_node.ts
@@ -29,7 +29,7 @@ import {
   immutableClass, KeyringNode
 } from '@aws-crypto/material-management-node'
 import { KMS } from 'aws-sdk' // eslint-disable-line no-unused-vars
-const getKmsClient = getClient(KMS)
+const getKmsClient = getClient(KMS, { customUserAgent: 'AwsEncryptionSdkJavascriptNodejs' })
 const cacheKmsClients = cacheClients(getKmsClient)
 
 export type KmsKeyringNodeInput = Partial<KmsKeyringInput<KMS>>