diff --git a/keyboards/takashicompany/left_slinger/keyboard.json b/keyboards/takashicompany/left_slinger/keyboard.json
index 137de5c0035..f0e0862ddc6 100644
--- a/keyboards/takashicompany/left_slinger/keyboard.json
+++ b/keyboards/takashicompany/left_slinger/keyboard.json
@@ -4,10 +4,16 @@
     "maintainer": "takashicompany",
     "bootloader": "rp2040",
     "diode_direction": "COL2ROW",
+    "encoder": {
+        "rotary": [
+            {"pin_a": "GP14", "pin_b": "GP15"}
+        ]
+    },
     "features": {
         "bootmagic": true,
         "command": false,
         "console": false,
+        "encoder": true,
         "extrakey": true,
         "mousekey": true,
         "nkro": true
diff --git a/keyboards/takashicompany/left_slinger/keymaps/default/keymap.c b/keyboards/takashicompany/left_slinger/keymaps/default/keymap.c
index 5bf2989a196..a392a0c74f3 100644
--- a/keyboards/takashicompany/left_slinger/keymaps/default/keymap.c
+++ b/keyboards/takashicompany/left_slinger/keymaps/default/keymap.c
@@ -23,3 +23,9 @@ const uint16_t PROGMEM keymaps[][MATRIX_ROWS][MATRIX_COLS] = {
               KC_F, KC_G, KC_H
     )
 };
+
+#if defined(ENCODER_MAP_ENABLE)
+const uint16_t PROGMEM encoder_map[][NUM_ENCODERS][NUM_DIRECTIONS] = {
+    [0] =   { ENCODER_CCW_CW(KC_1, KC_2) }
+};
+#endif
diff --git a/keyboards/takashicompany/left_slinger/keymaps/default/rules.mk b/keyboards/takashicompany/left_slinger/keymaps/default/rules.mk
new file mode 100644
index 00000000000..a40474b4d5c
--- /dev/null
+++ b/keyboards/takashicompany/left_slinger/keymaps/default/rules.mk
@@ -0,0 +1 @@
+ENCODER_MAP_ENABLE = yes
\ No newline at end of file