Sign in

v1

latestOpenAPI 3.0.0Apache 2.0 License2026-07-171,1822,9897.4 MB

Creates a subnet in the specified VPC. For an IPv4 only subnet, specify an IPv4 CIDR block. If the VPC has an IPv6 CIDR block, you can create an IPv6 only subnet or a dual stack subnet instead. For an IPv6 only subnet, specify an IPv6 CIDR block. For a dual stack subnet, specify both an IPv4 CIDR block and an IPv6 CIDR block.

A subnet CIDR block must not overlap the CIDR block of an existing subnet in the VPC. After you create a subnet, you can't change its CIDR block.

The allowed size for an IPv4 subnet is between a /28 netmask (16 IP addresses) and a /16 netmask (65,536 IP addresses). Amazon Web Services reserves both the first four and the last IPv4 address in each subnet's CIDR block. They're not available for your use.

If you've associated an IPv6 CIDR block with your VPC, you can associate an IPv6 CIDR block with a subnet when you create it. The allowed block size for an IPv6 subnet is a /64 netmask.

If you add more than one subnet to a VPC, they're set up in a star topology with a logical router in the middle.

When you stop an instance in a subnet, it retains its private IPv4 address. It's therefore possible to have a subnet with no running instances (they're all stopped), but no remaining IP addresses available.

For more information, see Subnets in the Amazon Virtual Private Cloud User Guide.

get/#Action=CreateSubnet

Query parameters

ResourceType'capacity-reservation' | 'client-vpn-endpoint' | 'customer-gateway' | 'carrier-gateway' | 'coip-pool' | 'dedicated-host' | 'dhcp-options' | 'egress-only-internet-gateway' | 'elastic-ip' | 'elastic-gpu' | 'export-image-task' | 'export-instance-task' | 'fleet' | 'fpga-image' | 'host-reservation' | 'image' | 'import-image-task' | 'import-snapshot-task' | 'instance' | 'instance-event-window' | 'internet-gateway' | 'ipam' | 'ipam-pool' | 'ipam-scope' | 'ipv4pool-ec2' | 'ipv6pool-ec2' | 'key-pair' | 'launch-template' | 'local-gateway' | 'local-gateway-route-table' | 'local-gateway-virtual-interface' | 'local-gateway-virtual-interface-group' | 'local-gateway-route-table-vpc-association' | 'local-gateway-route-table-virtual-interface-group-association' | 'natgateway' | 'network-acl' | 'network-interface' | 'network-insights-analysis' | 'network-insights-path' | 'network-insights-access-scope' | 'network-insights-access-scope-analysis' | 'placement-group' | 'prefix-list' | 'replace-root-volume-task' | 'reserved-instances' | 'route-table' | 'security-group' | 'security-group-rule' | 'snapshot' | 'spot-fleet-request' | 'spot-instances-request' | 'subnet' | 'subnet-cidr-reservation' | 'traffic-mirror-filter' | 'traffic-mirror-session' | 'traffic-mirror-target' | 'transit-gateway' | 'transit-gateway-attachment' | 'transit-gateway-connect-peer' | 'transit-gateway-multicast-domain' | 'transit-gateway-policy-table' | 'transit-gateway-route-table' | 'transit-gateway-route-table-announcement' | 'volume' | 'vpc' | 'vpc-endpoint' | 'vpc-endpoint-connection' | 'vpc-endpoint-service' | 'vpc-endpoint-service-permission' | 'vpc-peering-connection' | 'vpn-connection' | 'vpn-gateway' | 'vpc-flow-log' | 'capacity-reservation-fleet' | 'traffic-mirror-filter-rule' | 'vpc-endpoint-connection-device-type' | 'verified-access-instance' | 'verified-access-group' | 'verified-access-endpoint' | 'verified-access-policy' | 'verified-access-trust-provider' | 'vpn-connection-device-type' | 'vpc-block-public-access-exclusion' | 'ipam-resource-discovery' | 'ipam-resource-discovery-association'

The type of resource to tag on creation.

The tags to assign to the subnet.

AvailabilityZonestring
<p>The Availability Zone or Local Zone for the subnet.</p> <p>Default: Amazon Web Services selects one for you. If you create more than one subnet in your VPC, we do not necessarily select a different zone for each subnet.</p> <p>To create a subnet in a Local Zone, set this value to the Local Zone ID, for example <code>us-west-2-lax-1a</code>. For information about the Regions that support Local Zones, see <a href="https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/using-regions-availability-zones.html#concepts-available-regions">Available Regions</a> in the <i>Amazon Elastic Compute Cloud User Guide</i>.</p> <p>To create a subnet in an Outpost, set this value to the Availability Zone for the Outpost and specify the Outpost ARN.</p>
AvailabilityZoneIdstring

The AZ ID or the Local Zone ID of the subnet.

CidrBlockstring
<p>The IPv4 network range for the subnet, in CIDR notation. For example, <code>10.0.0.0/24</code>. We modify the specified CIDR block to its canonical form; for example, if you specify <code>100.68.0.18/18</code>, we modify it to <code>100.68.0.0/18</code>.</p> <p>This parameter is not supported for an IPv6 only subnet.</p>
Ipv6CidrBlockstring
<p>The IPv6 network range for the subnet, in CIDR notation. The subnet size must use a /64 prefix length.</p> <p>This parameter is required for an IPv6 only subnet.</p>
OutpostArnstring

The Amazon Resource Name (ARN) of the Outpost. If you specify an Outpost ARN, you must also specify the Availability Zone of the Outpost subnet.

VpcIdstring required

The ID of the VPC.

DryRunboolean

Checks whether you have the required permissions for the action, without actually making the request, and provides an error response. If you have the required permissions, the error response is <code>DryRunOperation</code>. Otherwise, it is <code>UnauthorizedOperation</code>.

Ipv6Nativeboolean

Indicates whether to create an IPv6 only subnet.

Action'CreateSubnet' required
Version'2016-11-15' required

Response

Success