diff --git a/discovery/ec2/ec2.go b/discovery/ec2/ec2.go
index f382e2bea3..938fedf4ed 100644
--- a/discovery/ec2/ec2.go
+++ b/discovery/ec2/ec2.go
@@ -37,18 +37,19 @@ import (
 )
 
 const (
-	ec2Label              = model.MetaLabelPrefix + "ec2_"
-	ec2LabelAZ            = ec2Label + "availability_zone"
-	ec2LabelInstanceID    = ec2Label + "instance_id"
-	ec2LabelInstanceState = ec2Label + "instance_state"
-	ec2LabelInstanceType  = ec2Label + "instance_type"
-	ec2LabelPublicDNS     = ec2Label + "public_dns_name"
-	ec2LabelPublicIP      = ec2Label + "public_ip"
-	ec2LabelPrivateIP     = ec2Label + "private_ip"
-	ec2LabelSubnetID      = ec2Label + "subnet_id"
-	ec2LabelTag           = ec2Label + "tag_"
-	ec2LabelVPCID         = ec2Label + "vpc_id"
-	subnetSeparator       = ","
+	ec2Label                = model.MetaLabelPrefix + "ec2_"
+	ec2LabelAZ              = ec2Label + "availability_zone"
+	ec2LabelInstanceID      = ec2Label + "instance_id"
+	ec2LabelInstanceState   = ec2Label + "instance_state"
+	ec2LabelInstanceType    = ec2Label + "instance_type"
+	ec2LabelPublicDNS       = ec2Label + "public_dns_name"
+	ec2LabelPublicIP        = ec2Label + "public_ip"
+	ec2LabelPrivateIP       = ec2Label + "private_ip"
+	ec2LabelPrimarySubnetID = ec2Label + "primary_subnet_id"
+	ec2LabelSubnetID        = ec2Label + "subnet_id"
+	ec2LabelTag             = ec2Label + "tag_"
+	ec2LabelVPCID           = ec2Label + "vpc_id"
+	subnetSeparator         = ","
 )
 
 var (
@@ -256,6 +257,7 @@ func (d *Discovery) refresh() (tg *targetgroup.Group, err error) {
 
 				if inst.VpcId != nil {
 					labels[ec2LabelVPCID] = model.LabelValue(*inst.VpcId)
+					labels[ec2LabelPrimarySubnetID] = model.LabelValue(*inst.SubnetId)
 
 					// Deduplicate VPC Subnet IDs maintaining the order of the network interfaces returned by EC2.
 					var subnets []string
diff --git a/docs/configuration/configuration.md b/docs/configuration/configuration.md
index 6a164200b5..ece829bce1 100644
--- a/docs/configuration/configuration.md
+++ b/docs/configuration/configuration.md
@@ -401,6 +401,7 @@ The following meta labels are available on targets during [relabeling](#relabel_
 * `__meta_ec2_instance_id`: the EC2 instance ID
 * `__meta_ec2_instance_state`: the state of the EC2 instance
 * `__meta_ec2_instance_type`: the type of the EC2 instance
+* `__meta_ec2_primary_subnet_id`: the subnet ID of the primary network interface, if available
 * `__meta_ec2_private_ip`: the private IP address of the instance, if present
 * `__meta_ec2_public_dns_name`: the public DNS name of the instance, if available
 * `__meta_ec2_public_ip`: the public IP address of the instance, if available