Get all available regions supported by boto library for an AWS service, like S3

get_s3_regions.py

from botocore.loaders import create_loader
from botocore.regions import EndpointResolver

endpoints = create_loader().load_data('endpoints')
partitions = [part['partition'] for part in endpoints['partitions']]

for partition in partitions:
    s3_regions = EndpointResolver(endpoints).get_available_endpoints("s3", partition)

    aws_partition = next(
        filter(lambda part: part["partition"] == partition, endpoints['partitions'])
    )
    
    print(f"Partition: {partition}")

    for region in s3_regions:
        print(" -", aws_partition["regions"][region]["description"], region)

    print()

"""
Partition: aws
 - Africa (Cape Town) af-south-1
 - Asia Pacific (Hong Kong) ap-east-1
 - Asia Pacific (Tokyo) ap-northeast-1
 - Asia Pacific (Seoul) ap-northeast-2
 - Asia Pacific (Mumbai) ap-south-1
 - Asia Pacific (Singapore) ap-southeast-1
 - Asia Pacific (Sydney) ap-southeast-2
 - Canada (Central) ca-central-1
 - Europe (Frankfurt) eu-central-1
 - Europe (Stockholm) eu-north-1
 - Europe (Milan) eu-south-1
 - Europe (Ireland) eu-west-1
 - Europe (London) eu-west-2
 - Europe (Paris) eu-west-3
 - Middle East (Bahrain) me-south-1
 - South America (Sao Paulo) sa-east-1
 - US East (N. Virginia) us-east-1
 - US East (Ohio) us-east-2
 - US West (N. California) us-west-1
 - US West (Oregon) us-west-2

Partition: aws-cn
 - China (Beijing) cn-north-1
 - China (Ningxia) cn-northwest-1

Partition: aws-us-gov
 - AWS GovCloud (US-East) us-gov-east-1
 - AWS GovCloud (US-West) us-gov-west-1

Partition: aws-iso
 - US ISO East us-iso-east-1

Partition: aws-iso-b
 - US ISOB East (Ohio) us-isob-east-1
"""