diff --git a/aws/resource_aws_route_table_test.go b/aws/resource_aws_route_table_test.go
index 4e405be063b5..1c5f4fb2210a 100644
--- a/aws/resource_aws_route_table_test.go
+++ b/aws/resource_aws_route_table_test.go
@@ -698,7 +698,101 @@ func TestAccAWSRouteTable_IPv4_To_NatGateway(t *testing.T) {
 	})
 }
 
-func TestAccAWSRouteTable_IPv6_To_NetworkInterface(t *testing.T) {
+/*
+func TestAccAWSRouteTable_IPv4_To_NetworkInterface_Attached(t *testing.T) {
+	var routeTable ec2.RouteTable
+	resourceName := "aws_route_table.test"
+	rName := acctest.RandomWithPrefix("tf-acc-test")
+	destinationCidr := "10.2.0.0/16"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:      func() { testAccPreCheck(t) },
+		IDRefreshName: resourceName,
+		Providers:     testAccProviders,
+		CheckDestroy:  testAccCheckRouteTableDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAWSRouteTableConfigIpv4NetworkInterfaceAttached(rName, destinationCidr),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckRouteTableExists(resourceName, &routeTable),
+					testAccCheckAWSRouteTableNumberOfRoutes(&routeTable, 2),
+					testAccCheckResourceAttrAccountID(resourceName, "owner_id"),
+					resource.TestCheckResourceAttr(resourceName, "propagating_vgws.#", "0"),
+					resource.TestCheckResourceAttr(resourceName, "route.#", "1"),
+					tfawsresource.TestCheckTypeSetElemNestedAttrs(resourceName, "route.*", map[string]string{
+						"cidr_block":      destinationCidr,
+						"ipv6_cidr_block": "",
+					}),
+					resource.TestCheckResourceAttr(resourceName, "tags.%", "1"),
+					resource.TestCheckResourceAttr(resourceName, "tags.Name", rName),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+
+func TestAccAWSRouteTable_IPv4_To_NetworkInterface_TwoAttachments(t *testing.T) {
+	var routeTable ec2.RouteTable
+	resourceName := "aws_route_table.test"
+	eni1ResourceName := "aws_network_interface.test1"
+	eni2ResourceName := "aws_network_interface.test2"
+	rName := acctest.RandomWithPrefix("tf-acc-test")
+	destinationCidr := "10.2.0.0/16"
+
+	resource.ParallelTest(t, resource.TestCase{
+		PreCheck:      func() { testAccPreCheck(t) },
+		IDRefreshName: resourceName,
+		Providers:     testAccProviders,
+		CheckDestroy:  testAccCheckRouteTableDestroy,
+		Steps: []resource.TestStep{
+			{
+				Config: testAccAWSRouteTableConfigIpv4NetworkInterfaceTwoAttachments(rName, destinationCidr, eni1ResourceName),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckRouteTableExists(resourceName, &routeTable),
+					testAccCheckAWSRouteTableNumberOfRoutes(&routeTable, 2),
+					testAccCheckResourceAttrAccountID(resourceName, "owner_id"),
+					resource.TestCheckResourceAttr(resourceName, "propagating_vgws.#", "0"),
+					resource.TestCheckResourceAttr(resourceName, "route.#", "1"),
+					tfawsresource.TestCheckTypeSetElemNestedAttrs(resourceName, "route.*", map[string]string{
+						"cidr_block":      destinationCidr,
+						"ipv6_cidr_block": "",
+					}),
+					resource.TestCheckResourceAttr(resourceName, "tags.%", "1"),
+					resource.TestCheckResourceAttr(resourceName, "tags.Name", rName),
+				),
+			},
+			{
+				Config: testAccAWSRouteTableConfigIpv4NetworkInterfaceTwoAttachments(rName, destinationCidr, eni2ResourceName),
+				Check: resource.ComposeTestCheckFunc(
+					testAccCheckRouteTableExists(resourceName, &routeTable),
+					testAccCheckAWSRouteTableNumberOfRoutes(&routeTable, 2),
+					testAccCheckResourceAttrAccountID(resourceName, "owner_id"),
+					resource.TestCheckResourceAttr(resourceName, "propagating_vgws.#", "0"),
+					resource.TestCheckResourceAttr(resourceName, "route.#", "1"),
+					tfawsresource.TestCheckTypeSetElemNestedAttrs(resourceName, "route.*", map[string]string{
+						"cidr_block":      destinationCidr,
+						"ipv6_cidr_block": "",
+					}),
+					resource.TestCheckResourceAttr(resourceName, "tags.%", "1"),
+					resource.TestCheckResourceAttr(resourceName, "tags.Name", rName),
+				),
+			},
+			{
+				ResourceName:      resourceName,
+				ImportState:       true,
+				ImportStateVerify: true,
+			},
+		},
+	})
+}
+*/
+
+func TestAccAWSRouteTable_IPv6_To_NetworkInterface_Unattached(t *testing.T) {
 	var routeTable ec2.RouteTable
 	resourceName := "aws_route_table.test"
 	rName := acctest.RandomWithPrefix("tf-acc-test")
@@ -711,7 +805,7 @@ func TestAccAWSRouteTable_IPv6_To_NetworkInterface(t *testing.T) {
 		CheckDestroy:  testAccCheckRouteTableDestroy,
 		Steps: []resource.TestStep{
 			{
-				Config: testAccAWSRouteTableConfigIpv6NetworkInterface(rName, destinationCidr),
+				Config: testAccAWSRouteTableConfigIpv6NetworkInterfaceUnattached(rName, destinationCidr),
 				Check: resource.ComposeTestCheckFunc(
 					testAccCheckRouteTableExists(resourceName, &routeTable),
 					testAccCheckAWSRouteTableNumberOfRoutes(&routeTable, 3),
@@ -1492,7 +1586,170 @@ resource "aws_route_table" "test" {
 `, rName, destinationCidr)
 }
 
-func testAccAWSRouteTableConfigIpv6NetworkInterface(rName, destinationCidr string) string {
+/*
+func testAccAWSRouteTableConfigIpv4NetworkInterfaceAttached(rName, destinationCidr string) string {
+	return composeConfig(
+		testAccLatestAmazonLinuxHvmEbsAmiConfig(),
+		testAccAvailableEc2InstanceTypeForRegion("t3.micro", "t2.micro"),
+		fmt.Sprintf(`
+data "aws_availability_zones" "current" {
+  # Exclude usw2-az4 (us-west-2d) as it has limited instance types.
+  exclude_zone_ids = ["usw2-az4"]
+  state            = "available"
+
+  filter {
+    name   = "opt-in-status"
+    values = ["opt-in-not-required"]
+  }
+}
+
+resource "aws_vpc" "test" {
+  cidr_block = "10.1.0.0/16"
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_subnet" "test" {
+  cidr_block        = "10.1.1.0/24"
+  vpc_id            = aws_vpc.test.id
+  availability_zone = data.aws_availability_zones.current.names[0]
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_network_interface" "test" {
+  subnet_id = aws_subnet.test.id
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_instance" "test" {
+  ami           = data.aws_ami.amzn-ami-minimal-hvm-ebs.id
+  instance_type = data.aws_ec2_instance_type_offering.available.instance_type
+
+  network_interface {
+    device_index         = 0
+    network_interface_id = aws_network_interface.test.id
+  }
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_route_table" "test" {
+  vpc_id = aws_vpc.test.id
+
+  route {
+    cidr_block           = %[2]q
+    network_interface_id = aws_network_interface.test.id
+  }
+
+  tags = {
+    Name = %[1]q
+  }
+
+  # Wait for the ENI attachment.
+  depends_on = [aws_instance.test]
+}
+`, rName, destinationCidr))
+}
+
+func testAccAWSRouteTableConfigIpv4NetworkInterfaceTwoAttachments(rName, destinationCidr, targetResourceName string) string {
+	return composeConfig(
+		testAccLatestAmazonLinuxHvmEbsAmiConfig(),
+		testAccAvailableEc2InstanceTypeForRegion("t3.micro", "t2.micro"),
+		fmt.Sprintf(`
+data "aws_availability_zones" "current" {
+  # Exclude usw2-az4 (us-west-2d) as it has limited instance types.
+  exclude_zone_ids = ["usw2-az4"]
+  state            = "available"
+
+  filter {
+    name   = "opt-in-status"
+    values = ["opt-in-not-required"]
+  }
+}
+
+resource "aws_vpc" "test" {
+  cidr_block = "10.1.0.0/16"
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_subnet" "test" {
+  cidr_block        = "10.1.1.0/24"
+  vpc_id            = aws_vpc.test.id
+  availability_zone = data.aws_availability_zones.current.names[0]
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_network_interface" "test1" {
+  subnet_id = aws_subnet.test.id
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_network_interface" "test2" {
+  subnet_id = aws_subnet.test.id
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_instance" "test" {
+  ami           = data.aws_ami.amzn-ami-minimal-hvm-ebs.id
+  instance_type = data.aws_ec2_instance_type_offering.available.instance_type
+
+  network_interface {
+    device_index         = 0
+    network_interface_id = aws_network_interface.test1.id
+  }
+
+  network_interface {
+    device_index         = 1
+    network_interface_id = aws_network_interface.test2.id
+  }
+
+  tags = {
+    Name = %[1]q
+  }
+}
+
+resource "aws_route_table" "test" {
+  vpc_id = aws_vpc.test.id
+
+  route {
+    cidr_block           = %[2]q
+    network_interface_id = %[3]s.id
+  }
+
+  tags = {
+    Name = %[1]q
+  }
+
+  # Wait for the ENI attachment.
+  depends_on = [aws_instance.test]
+}
+`, rName, destinationCidr, targetResourceName))
+}
+*/
+
+func testAccAWSRouteTableConfigIpv6NetworkInterfaceUnattached(rName, destinationCidr string) string {
 	return fmt.Sprintf(`
 resource "aws_vpc" "test" {
   cidr_block                       = "10.1.0.0/16"