diff --git a/nav.py b/nav.py
index fa99dc9..f781d98 100644
--- a/nav.py
+++ b/nav.py
@@ -20,6 +20,7 @@ DISTANCES = {
     ("gateway", "milliways"): 42.0,
     ("ceres", "vesta"): 96.0,
     ("ceres", "europa"): 404.0,
+    ("europa", "io"): 0.25,
 }
 
 # Every route starts at Earth.
@@ -34,6 +35,7 @@ ROUTES = {
     "milliways": ["earth", "gateway", "milliways"],
     "vesta": ["earth", "gateway", "mars", "ceres", "vesta"],
     "europa": ["earth", "gateway", "mars", "ceres", "europa"],
+    "io": ["earth", "gateway", "mars", "ceres", "europa", "io"],
 }
 
 NAMES = {
@@ -49,6 +51,7 @@ NAMES = {
     "milliways": "Restaurant at the End of the Universe",
     "vesta": "Vesta",
     "europa": "Europa",
+    "io": "Io",
 }
 
 CRUISE_SPEED = 0.87  # million km per day