How to see all running Amazon EC2 instances across all regions?

Nov 2021 Edit: AWS has recently launched the Amazon EC2 Global View with initial support for Instances, VPCs, Subnets, Security Groups and Volumes.

See the announcement or documentation for more details

A non-obvious GUI option is the Tag Editor in the Resource Groups console. Here you can find all instances across all regions, even if the instances were not tagged.

I don't think you can currently do this in the AWS GUI. But here is a way to list all your instances across all regions with the AWS CLI:

for region in `aws ec2 describe-regions --region us-east-1 --output text | cut -f4`
do
     echo -e "\nListing Instances in region:'$region'..."
     aws ec2 describe-instances --region $region
done

Taken from here (If you want to see full discussion)

Also, if you're getting a

You must specify a region. You can also configure your region by running "aws configure"

You can do so with aws configure set region us-east-1, thanks @Sabuncu for the comment.

Update

Now (in 2019) the cut command should be applied on the 4th field: cut -f4

In Console

Go to VPC dashboard https://console.aws.amazon.com/vpc/home and click on Running instances -> See all regions.

In CLI

Add this for example to .bashrc. Reload it source ~/.bashrc, and run it

Note: Except for aws CLI you need to have jq installed

function aws.print-all-instances() {
  REGIONS=`aws ec2 describe-regions --region us-east-1 --output text --query Regions[*].[RegionName]`
  for REGION in $REGIONS
  do
    echo -e "\nInstances in '$REGION'..";
    aws ec2 describe-instances --region $REGION | \
      jq '.Reservations[].Instances[] | "EC2: \(.InstanceId): \(.State.Name)"'
  done
}

Example output:

$ aws.print-all-instances 

Listing Instances in region: 'eu-north-1'..
"EC2: i-0548d1de00c39f923: terminated"
"EC2: i-0fadd093234a1c21d: running"

Listing Instances in region: 'ap-south-1'..

Listing Instances in region: 'eu-west-3'..

Listing Instances in region: 'eu-west-2'..

Listing Instances in region: 'eu-west-1'..

Listing Instances in region: 'ap-northeast-2'..

Listing Instances in region: 'ap-northeast-1'..

Listing Instances in region: 'sa-east-1'..

Listing Instances in region: 'ca-central-1'..

Listing Instances in region: 'ap-southeast-1'..

Listing Instances in region: 'ap-southeast-2'..

Listing Instances in region: 'eu-central-1'..

Listing Instances in region: 'us-east-1'..

Listing Instances in region: 'us-east-2'..

Listing Instances in region: 'us-west-1'..

Listing Instances in region: 'us-west-2'..