diff --git a/src/custom/backend.ts b/src/custom/backend.ts
index 9c792de..bed7ebd 100644
--- a/src/custom/backend.ts
+++ b/src/custom/backend.ts
@@ -40,6 +40,10 @@ const region =
     process.env.RUNS_ON_AWS_REGION ||
     process.env.AWS_REGION ||
     process.env.AWS_DEFAULT_REGION;
+const forcePathStyle = Boolean(
+    process.env.RUNS_ON_S3_FORCE_PATH_STYLE ||
+    process.env.AWS_S3_FORCE_PATH_STYLE
+);
 
 const uploadQueueSize = Number(process.env.UPLOAD_QUEUE_SIZE || "4");
 const uploadPartSize =
@@ -48,7 +52,7 @@ const downloadQueueSize = Number(process.env.DOWNLOAD_QUEUE_SIZE || "8");
 const downloadPartSize =
     Number(process.env.DOWNLOAD_PART_SIZE || "16") * 1024 * 1024;
 
-const s3Client = new S3Client({ region });
+const s3Client = new S3Client({ region, forcePathStyle });
 
 export function getCacheVersion(
     paths: string[],