diff --git a/bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3InstallationService.java b/bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3InstallationService.java
index b406219d9..4053fc307 100644
--- a/bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3InstallationService.java
+++ b/bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3InstallationService.java
@@ -14,10 +14,12 @@
 import software.amazon.awssdk.core.ResponseBytes;
 import software.amazon.awssdk.core.sync.RequestBody;
 import software.amazon.awssdk.core.sync.ResponseTransformer;
+import software.amazon.awssdk.regions.Region;
 import software.amazon.awssdk.services.s3.S3Client;
 import software.amazon.awssdk.services.s3.model.*;
 
 import java.io.IOException;
+import java.net.URI;
 import java.nio.charset.StandardCharsets;
 import java.util.Map;
 import java.util.Optional;
@@ -26,23 +28,38 @@
 public class AmazonS3InstallationService implements InstallationService {
 
     private final String bucketName;
-    private AwsCredentialsProvider credentialsProvider;
+
+    private final AwsCredentialsProvider credentialsProvider;
+    private final Region region;
+    private final URI endpointOverride;
+
     private boolean historicalDataEnabled;
 
     public AmazonS3InstallationService(String bucketName) {
-        this(bucketName, null);
+        this(bucketName, DefaultCredentialsProvider.create(), null, null);
     }
 
     public AmazonS3InstallationService(String bucketName, AwsCredentialsProvider credentialsProvider) {
+        this(bucketName, credentialsProvider, null, null);
+    }
+
+    public AmazonS3InstallationService(
+            String bucketName,
+            AwsCredentialsProvider credentialsProvider,
+            Region region,
+            String endpointOverride
+    ) {
         this.bucketName = bucketName;
         this.credentialsProvider = credentialsProvider;
+        this.region = region != null ? region : Region.of(System.getenv("AWS_REGION"));
+        this.endpointOverride = (endpointOverride != null && !endpointOverride.isEmpty()) ? URI.create(endpointOverride) : null;
     }
 
     @Override
     public Initializer initializer() {
         return (app) -> {
             // The first access to S3 tends to be slow on AWS Lambda.
-            AwsCredentials credentials = createCredentials(getAwsCredentialsProvider());
+            AwsCredentials credentials = createCredentials(this.credentialsProvider);
             if (credentials == null || credentials.accessKeyId() == null) {
                 throw new IllegalStateException("AWS credentials not found");
             }
@@ -303,19 +320,16 @@ private Installer toInstaller(ResponseBytes<GetObjectResponse> s3Object) throws
         return JsonOps.fromJson(json, DefaultInstaller.class);
     }
 
-    protected AwsCredentialsProvider getAwsCredentialsProvider() {
-        if (this.credentialsProvider == null) {
-            this.credentialsProvider = DefaultCredentialsProvider.create();
-        }
-        return this.credentialsProvider;
-    }
-
     protected AwsCredentials createCredentials(AwsCredentialsProvider provider) {
         return provider.resolveCredentials();
     }
 
     protected S3Client createS3Client() {
-        return S3Client.builder().credentialsProvider(this.credentialsProvider).build();
+        return S3Client.builder()
+                .credentialsProvider(this.credentialsProvider)
+                .region(this.region)
+                .endpointOverride(this.endpointOverride)
+                .build();
     }
 
     private String getInstallerKey(Installer i) {
diff --git a/bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3OAuthStateService.java b/bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3OAuthStateService.java
index 9f982a226..5b4ef17b5 100644
--- a/bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3OAuthStateService.java
+++ b/bolt/src/main/java/com/slack/api/bolt/service/builtin/AmazonS3OAuthStateService.java
@@ -5,13 +5,14 @@
 import lombok.extern.slf4j.Slf4j;
 import software.amazon.awssdk.auth.credentials.AwsCredentials;
 import software.amazon.awssdk.auth.credentials.AwsCredentialsProvider;
-import software.amazon.awssdk.auth.credentials.DefaultCredentialsProvider;
 import software.amazon.awssdk.core.ResponseBytes;
 import software.amazon.awssdk.core.sync.RequestBody;
 import software.amazon.awssdk.core.sync.ResponseTransformer;
+import software.amazon.awssdk.regions.Region;
 import software.amazon.awssdk.services.s3.S3Client;
 import software.amazon.awssdk.services.s3.model.*;
 
+import java.net.URI;
 import java.nio.charset.StandardCharsets;
 
 /**
@@ -23,22 +24,36 @@
 public class AmazonS3OAuthStateService implements OAuthStateService {
 
     private final String bucketName;
-    private AwsCredentialsProvider credentialsProvider;
+
+    private final AwsCredentialsProvider credentialsProvider;
+    private final Region region;
+    private final URI endpointOverride;
 
     public AmazonS3OAuthStateService(String bucketName) {
         this(bucketName, null);
     }
 
     public AmazonS3OAuthStateService(String bucketName, AwsCredentialsProvider credentialsProvider) {
+        this(bucketName, credentialsProvider, null, null);
+    }
+
+    public AmazonS3OAuthStateService(
+            String bucketName,
+            AwsCredentialsProvider credentialsProvider,
+            Region region,
+            String endpointOverride
+    ) {
         this.bucketName = bucketName;
         this.credentialsProvider = credentialsProvider;
+        this.region = region != null ? region : Region.of(System.getenv("AWS_REGION"));
+        this.endpointOverride = (endpointOverride != null && !endpointOverride.isEmpty()) ? URI.create(endpointOverride) : null;
     }
 
     @Override
     public Initializer initializer() {
         return (app) -> {
             // The first access to S3 tends to be slow on AWS Lambda.
-            AwsCredentials credentials = createCredentials(getAwsCredentialsProvider());
+            AwsCredentials credentials = createCredentials(this.credentialsProvider);
             if (credentials == null || credentials.accessKeyId() == null) {
                 throw new IllegalStateException("AWS credentials not found");
             }
@@ -102,19 +117,16 @@ public void deleteStateFromDatastore(String state) throws Exception {
         }
     }
 
-    protected AwsCredentialsProvider getAwsCredentialsProvider() {
-        if (this.credentialsProvider == null) {
-            this.credentialsProvider = DefaultCredentialsProvider.create();
-        }
-        return this.credentialsProvider;
-    }
-
     protected AwsCredentials createCredentials(AwsCredentialsProvider provider) {
         return provider.resolveCredentials();
     }
 
     protected S3Client createS3Client() {
-        return S3Client.builder().credentialsProvider(this.credentialsProvider).build();
+        return S3Client.builder()
+                .credentialsProvider(this.credentialsProvider)
+                .region(this.region)
+                .endpointOverride(this.endpointOverride)
+                .build();
     }
 
     private String getKey(String state) {