diff --git a/moto/ec2/models.py b/moto/ec2/models.py
index 501615722..548740a00 100644
--- a/moto/ec2/models.py
+++ b/moto/ec2/models.py
@@ -342,6 +342,9 @@ class Instance(BotoInstance, TaggedEC2Resource):
         if self.subnet_id:
             subnet = ec2_backend.get_subnet(self.subnet_id)
             self.vpc_id = subnet.vpc_id
+            self._placement.zone = subnet.availability_zone
+        else:
+            self._placement.zone = ec2_backend.region_name + 'a'
 
         self.block_device_mapping = BlockDeviceMapping()
 
diff --git a/tests/test_ec2/test_instances.py b/tests/test_ec2/test_instances.py
index 0dda4eb9c..e80d1f979 100644
--- a/tests/test_ec2/test_instances.py
+++ b/tests/test_ec2/test_instances.py
@@ -51,21 +51,23 @@ def test_instance_launch_and_terminate():
     reservations[0].id.should.equal(reservation.id)
     instances = reservations[0].instances
     instances.should.have.length_of(1)
-    instances[0].id.should.equal(instance.id)
-    instances[0].state.should.equal('running')
-    instances[0].launch_time.should.equal("2014-01-01T05:00:00.000Z")
-    instances[0].vpc_id.should.equal(None)
+    instance = instances[0]
+    instance.id.should.equal(instance.id)
+    instance.state.should.equal('running')
+    instance.launch_time.should.equal("2014-01-01T05:00:00.000Z")
+    instance.vpc_id.should.equal(None)
+    instance.placement.should.equal('us-east-1a')
 
-    root_device_name = instances[0].root_device_name
-    instances[0].block_device_mapping[root_device_name].status.should.equal('in-use')
-    volume_id = instances[0].block_device_mapping[root_device_name].volume_id
+    root_device_name = instance.root_device_name
+    instance.block_device_mapping[root_device_name].status.should.equal('in-use')
+    volume_id = instance.block_device_mapping[root_device_name].volume_id
     volume_id.should.match(r'vol-\w+')
 
     volume = conn.get_all_volumes(volume_ids=[volume_id])[0]
     volume.attach_data.instance_id.should.equal(instance.id)
     volume.status.should.equal('in-use')
 
-    conn.terminate_instances([instances[0].id])
+    conn.terminate_instances([instance.id])
 
     reservations = conn.get_all_instances()
     instance = reservations[0].instances[0]