diff --git a/lib/swift_context.py b/lib/swift_context.py
index a3a6e1c..5f17395 100644
--- a/lib/swift_context.py
+++ b/lib/swift_context.py
@@ -21,7 +21,8 @@ from charmhelpers.contrib.hahelpers.cluster import (
     determine_apache_port,
 )
 from charmhelpers.contrib.network.ip import (
-    get_ipv6_addr
+    format_ipv6_addr,
+    get_ipv6_addr,
 )
 from charmhelpers.contrib.openstack.utils import get_host_ip
 
@@ -171,6 +172,12 @@ class SwiftIdentityContext(OSContextGenerator):
                 if context_complete(ks_auth):
                     ctxt.update(ks_auth)
 
+        if config('prefer-ipv6'):
+            for key in ['keystone_host', 'service_host']:
+                host = ctxt.get(key)
+                if host:
+                    ctxt[key] = format_ipv6_addr(host)
+
         return ctxt