Bucket naming rules - Amazon Simple Storage Service
Services or capabilities described in Amazon Web Services documentation might vary by Region. To see the differences applicable to the China Regions, see Getting Started with Amazon Web Services in China (PDF).

Bucket naming rules

The following rules apply for naming general purpose buckets and directory buckets in Amazon S3:

General purpose buckets naming rules

The following naming rules apply for general purpose buckets.

  • Bucket names must be between 3 (min) and 63 (max) characters long.

  • Bucket names can consist only of lowercase letters, numbers, dots (.), and hyphens (-).

  • Bucket names must begin and end with a letter or number.

  • Bucket names must not contain two adjacent periods.

  • Bucket names must not be formatted as an IP address (for example,

  • Bucket names must not start with the prefix xn--.

  • Bucket names must not start with the prefix sthree- and the prefix sthree-configurator.

  • Bucket names must not end with the suffix -s3alias. This suffix is reserved for access point alias names. For more information, see Using a bucket-style alias for your S3 bucket access point.

  • Bucket names must not end with the suffix --ol-s3. This suffix is reserved for Object Lambda Access Point alias names. For more information, see How to use a bucket-style alias for your S3 bucket Object Lambda Access Point.

  • Bucket names must be unique across all Amazon Web Services accounts in all the Amazon Web Services Regions within a partition. A partition is a grouping of Regions. Amazon currently has three partitions: aws (Standard Regions), aws-cn (China Regions), and aws-us-gov (Amazon GovCloud (US)).

  • A bucket name cannot be used by another Amazon Web Services account in the same partition until the bucket is deleted.

  • Buckets used with Amazon S3 Transfer Acceleration can't have dots (.) in their names. For more information about Transfer Acceleration, see Configuring fast, secure file transfers using Amazon S3 Transfer Acceleration.

For best compatibility, we recommend that you avoid using dots (.) in bucket names, except for buckets that are used only for static website hosting. If you include dots in a bucket's name, you can't use virtual-host-style addressing over HTTPS, unless you perform your own certificate validation. This is because the security certificates used for virtual hosting of buckets don't work for buckets with dots in their names.

This limitation doesn't affect buckets used for static website hosting, because static website hosting is only available over HTTP. For more information about virtual-host-style addressing, see Virtual hosting of buckets. For more information about static website hosting, see Hosting a static website using Amazon S3.


Before March 1, 2018, buckets created in the US East (N. Virginia) Region could have names that were up to 255 characters long and included uppercase letters and underscores. Beginning March 1, 2018, new buckets in US East (N. Virginia) must conform to the same rules applied in all other Regions.

For information on object key names, see Creating object key names.

Example general purpose bucket names

The following example bucket names are valid and follow the recommended naming guidelines for general purpose buckets:

  • docexamplebucket1

  • log-delivery-march-2020

  • my-hosted-content

The following example bucket names are valid but not recommended for uses other than static website hosting:

  • docexamplewebsite.com

  • www.docexamplewebsite.com

  • my.example.s3.bucket

The following example bucket names are not valid:

  • doc_example_bucket (contains underscores)

  • DocExampleBucket (contains uppercase letters)

  • doc-example-bucket- (ends with a hyphen)

Directory bucket naming rules

Directory bucket names must:

  • Be unique within the chosen Amazon Web Services Region and Availability Zone.

  • Be no more than 3–63 characters long, including the suffix.

  • Consists only of lowercase letters, numbers and hyphens (-).

  • Begin and end with a letter or number.

  • All bucket names must include the following suffix: azid--x-s3.

    A suffix is added to the base name that you provide. This suffix includes the Availability Zone ID of the Availability Zone that you chose.