👀 Views: 90 💬 Answers: 1 📅 Created: 2025-06-09

AWS Lambda S3 Permissions Cross-Region Python

I'm working with an scenario where my AWS Lambda function, which is deployed in the us-east-1 region, is unable to access objects in an S3 bucket located in the us-west-2 region. The Lambda function throws a `AccessDenied` behavior when trying to get an object from the S3 bucket: ``` An behavior occurred (AccessDenied) when calling the GetObject operation: Access Denied ``` I've double-checked my Lambda execution role, and it has the necessary permissions: ```json { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Action": "s3:GetObject", "Resource": "arn:aws:s3:::my-bucket-name/*" } ] } ``` I also configured the S3 bucket policy to allow access from my Lambda function's role, but it still fails: ```json { "Version": "2012-10-17", "Statement": [ { "Effect": "Allow", "Principal": { "AWS": "arn:aws:iam::123456789012:role/my-lambda-role" }, "Action": "s3:GetObject", "Resource": "arn:aws:s3:::my-bucket-name/*" } ] } ``` I've ensured that there are no conflicting policies that might restrict access. I've also looked at the S3 Block Public Access settings and confirmed they are configured correctly. I tried adding the cross-region access explicitly to the bucket policy, but I still get the same `AccessDenied` behavior. Is there something I’m missing or any best practices to configure cross-region access correctly between Lambda and S3?