diff --git a/builder/amazon/common/access_config.go b/builder/amazon/common/access_config.go
index 59ef90c2b..bf295e535 100644
--- a/builder/amazon/common/access_config.go
+++ b/builder/amazon/common/access_config.go
@@ -80,8 +80,7 @@ func (c *AccessConfig) Session() (*session.Session, error) {
 	return c.session, nil
 }
 
-// Region returns the aws.Region object for access to AWS services, requesting
-// the region from the instance metadata if possible.
+// region returns either the region from config or region from metadata service
 func (c *AccessConfig) region() (string, error) {
 	if c.RawRegion != "" {
 		if !c.SkipValidation {
diff --git a/builder/amazon/common/ami_config.go b/builder/amazon/common/ami_config.go
index 09b25479a..7dfe1af88 100644
--- a/builder/amazon/common/ami_config.go
+++ b/builder/amazon/common/ami_config.go
@@ -41,20 +41,21 @@ func stringInSlice(s []string, searchstr string) bool {
 func (c *AMIConfig) Prepare(accessConfig *AccessConfig, ctx *interpolate.Context) []error {
 	var errs []error
 
-	session, err := accessConfig.Session()
-	if err != nil {
-		errs = append(errs, err)
+	if accessConfig != nil {
+		session, err := accessConfig.Session()
+		if err != nil {
+			errs = append(errs, err)
+		}
+		region := *session.Config.Region
+		if stringInSlice(c.AMIRegions, region) {
+			errs = append(errs, fmt.Errorf("Cannot copy AMI to AWS session region '%s', please remove it from `ami_regions`.", region))
+		}
 	}
-	region := *session.Config.Region
 
 	if c.AMIName == "" {
 		errs = append(errs, fmt.Errorf("ami_name must be specified"))
 	}
 
-	if stringInSlice(c.AMIRegions, region) {
-		errs = append(errs, fmt.Errorf("Cannot copy AMI to AWS session region '%s', please remove it from `ami_regions`.", region))
-	}
-
 	if len(c.AMIRegions) > 0 {
 		regionSet := make(map[string]struct{})
 		regions := make([]string, 0, len(c.AMIRegions))
diff --git a/builder/amazon/common/ami_config_test.go b/builder/amazon/common/ami_config_test.go
index faa67c56d..5f130130c 100644
--- a/builder/amazon/common/ami_config_test.go
+++ b/builder/amazon/common/ami_config_test.go
@@ -13,12 +13,12 @@ func testAMIConfig() *AMIConfig {
 
 func TestAMIConfigPrepare_name(t *testing.T) {
 	c := testAMIConfig()
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatalf("shouldn't have err: %s", err)
 	}
 
 	c.AMIName = ""
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("should have error")
 	}
 }
@@ -26,22 +26,22 @@ func TestAMIConfigPrepare_name(t *testing.T) {
 func TestAMIConfigPrepare_regions(t *testing.T) {
 	c := testAMIConfig()
 	c.AMIRegions = nil
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatalf("shouldn't have err: %s", err)
 	}
 
 	c.AMIRegions = listEC2Regions()
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatalf("shouldn't have err: %s", err)
 	}
 
 	c.AMIRegions = []string{"foo"}
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("should have error")
 	}
 
 	c.AMIRegions = []string{"us-east-1", "us-west-1", "us-east-1"}
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatalf("bad: %s", err)
 	}
 
@@ -52,7 +52,7 @@ func TestAMIConfigPrepare_regions(t *testing.T) {
 
 	c.AMIRegions = []string{"custom"}
 	c.AMISkipRegionValidation = true
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatal("shouldn't have error")
 	}
 	c.AMISkipRegionValidation = false
@@ -63,7 +63,7 @@ func TestAMIConfigPrepare_regions(t *testing.T) {
 		"us-west-1": "789-012-3456",
 		"us-east-2": "456-789-0123",
 	}
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatal("shouldn't have error")
 	}
 
@@ -73,7 +73,7 @@ func TestAMIConfigPrepare_regions(t *testing.T) {
 		"us-west-1": "789-012-3456",
 		"us-east-2": "",
 	}
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatal("should have passed; we are able to use default KMS key if not sharing")
 	}
 
@@ -84,7 +84,7 @@ func TestAMIConfigPrepare_regions(t *testing.T) {
 		"us-west-1": "789-012-3456",
 		"us-east-2": "",
 	}
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("should have an error b/c can't use default KMS key if sharing")
 	}
 
@@ -94,7 +94,7 @@ func TestAMIConfigPrepare_regions(t *testing.T) {
 		"us-west-1": "789-012-3456",
 		"us-east-2": "456-789-0123",
 	}
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("should have error b/c theres a region in the key map that isn't in ami_regions")
 	}
 
@@ -103,7 +103,7 @@ func TestAMIConfigPrepare_regions(t *testing.T) {
 		"us-east-1": "123-456-7890",
 		"us-west-1": "789-012-3456",
 	}
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("should have error b/c theres a region in in ami_regions that isn't in the key map")
 	}
 
@@ -115,7 +115,7 @@ func TestAMIConfigPrepare_regions(t *testing.T) {
 		"us-east-1": "123-456-7890",
 		"us-west-1": "",
 	}
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("should have error b/c theres a region in in ami_regions that isn't in the key map")
 	}
 }
@@ -126,12 +126,12 @@ func TestAMIConfigPrepare_Share_EncryptedBoot(t *testing.T) {
 	c.AMIEncryptBootVolume = true
 
 	c.AMIKmsKeyId = ""
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("shouldn't be able to share ami with encrypted boot volume")
 	}
 
 	c.AMIKmsKeyId = "89c3fb9a-de87-4f2a-aedc-fddc5138193c"
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("shouldn't be able to share ami with encrypted boot volume")
 	}
 }
@@ -140,7 +140,7 @@ func TestAMINameValidation(t *testing.T) {
 	c := testAMIConfig()
 
 	c.AMIName = "aa"
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("shouldn't be able to have an ami name with less than 3 characters")
 	}
 
@@ -149,22 +149,22 @@ func TestAMINameValidation(t *testing.T) {
 		longAmiName += "a"
 	}
 	c.AMIName = longAmiName
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("shouldn't be able to have an ami name with great than 128 characters")
 	}
 
 	c.AMIName = "+aaa"
-	if err := c.Prepare(nil); err == nil {
+	if err := c.Prepare(nil, nil); err == nil {
 		t.Fatal("shouldn't be able to have an ami name with invalid characters")
 	}
 
 	c.AMIName = "fooBAR1()[] ./-'@_"
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatal("should be able to use all of the allowed AMI characters")
 	}
 
 	c.AMIName = `xyz-base-2017-04-05-1934`
-	if err := c.Prepare(nil); err != nil {
+	if err := c.Prepare(nil, nil); err != nil {
 		t.Fatalf("expected `xyz-base-2017-04-05-1934` to pass validation.")
 	}