EC2 outbound data transfer cost to S3 Gateway Endpoint

Question

If I create an S3 Gateway Endpoint in a VPC and the EC2 instances within the VPC use this S3 Gateway Endpoint to connect to S3:

I understand that using the S3 Gateway Endpoint does not incur additional charges. However, how is the outbound data transfer from EC2 to the S3 Gateway Endpoint calculated?

1. Is it considered as same AZ data transfer with no charges?
2. Or is it considered as cross AZ data transfer and thus incurs charges?

Brettski-AWS · Accepted Answer

There are no data charges (inbound or outbound) for data traversing the S3 Gateway Endpoint. You should enable the endpoint in each AZ where it is required (which means there is no cross-AZ charges to think about).

Note that there are still charges for API calls.

Thanniru Anil Kumar · Answer

**1. No Additional Charges for Using the S3 Gateway Endpoint:**

The S3 Gateway Endpoint itself is free to use. You do not incur any charges for using the endpoint to route traffic between your EC2 instances and S3.

**2. Outbound Data Transfer Costs:**

**Same Availability Zone (AZ):** If your EC2 instance and the S3 Gateway Endpoint are in the same Availability Zone, there are no data transfer charges. The data transfer from the EC2 instance to S3 via the Gateway Endpoint is considered as local (intra-AZ) traffic, which is free.

**Cross Availability Zone (AZ):** If your EC2 instance is in a different Availability Zone from the S3 Gateway Endpoint, the data transfer between the EC2 instance and the Gateway Endpoint is considered cross-AZ traffic. Cross-AZ data transfer typically incurs a cost.

**Summary**

**Intra-AZ Data Transfer:** Free when the EC2 instance and S3 Gateway Endpoint are in the same AZ.

**Cross-AZ Data Transfer**: Charged according to the standard cross-AZ data transfer rates when the EC2 instance and S3 Gateway Endpoint are in different AZs.

EC2 outbound data transfer cost to S3 Gateway Endpoint

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