diff --git a/IPython/terminal/prompts.py b/IPython/terminal/prompts.py
index ee2c5d7..3f5c07b 100644
--- a/IPython/terminal/prompts.py
+++ b/IPython/terminal/prompts.py
@@ -17,7 +17,12 @@ class Prompts(object):
     def vi_mode(self):
         if (getattr(self.shell.pt_app, 'editing_mode', None) == EditingMode.VI
                 and self.shell.prompt_includes_vi_mode):
-            return '['+str(self.shell.pt_app.app.vi_state.input_mode)[3:6]+'] '
+            mode = str(self.shell.pt_app.app.vi_state.input_mode)
+            if mode.startswith('InputMode.'):
+                mode = mode[10:13].lower()
+            elif mode.startswith('vi-'):
+                mode = mode[3:6]
+            return '['+mode+'] '
         return ''