diff --git a/src/babashka/main.clj b/src/babashka/main.clj
index f7f5371e..a224eed3 100644
--- a/src/babashka/main.clj
+++ b/src/babashka/main.clj
@@ -112,7 +112,8 @@
                      (let [options (next options)]
                        (recur (next options)
                               (assoc opts-map
-                                     :socket-repl (first options))))
+                                     :socket-repl (or (first options)
+                                                      "1666"))))
                      ("--eval", "-e")
                      (let [options (next options)]
                        (recur (next options)