diff --git a/mediapipe/tasks/python/test/vision/image_segmenter_test.py b/mediapipe/tasks/python/test/vision/image_segmenter_test.py
index aa557281f..de0a263f3 100644
--- a/mediapipe/tasks/python/test/vision/image_segmenter_test.py
+++ b/mediapipe/tasks/python/test/vision/image_segmenter_test.py
@@ -15,7 +15,6 @@
 
 import enum
 import os
-from typing import List
 from unittest import mock
 
 from absl.testing import absltest
@@ -34,7 +33,6 @@ ImageSegmenterResult = image_segmenter.ImageSegmenterResult
 _BaseOptions = base_options_module.BaseOptions
 _Image = image_module.Image
 _ImageFormat = image_frame.ImageFormat
-_Activation = image_segmenter.ImageSegmenterOptions.Activation
 _ImageSegmenter = image_segmenter.ImageSegmenter
 _ImageSegmenterOptions = image_segmenter.ImageSegmenterOptions
 _RUNNING_MODE = vision_task_running_mode.VisionTaskRunningMode
@@ -191,7 +189,7 @@ class ImageSegmenterTest(parameterized.TestCase):
     # Run segmentation on the model in CONFIDENCE_MASK mode.
     options = _ImageSegmenterOptions(
         base_options=base_options, output_category_mask=False,
-        output_confidence_masks=True, activation=_Activation.SOFTMAX
+        output_confidence_masks=True
     )
 
     with _ImageSegmenter.create_from_options(options) as segmenter:
diff --git a/mediapipe/tasks/python/vision/image_segmenter.py b/mediapipe/tasks/python/vision/image_segmenter.py
index 102773173..c5204db47 100644
--- a/mediapipe/tasks/python/vision/image_segmenter.py
+++ b/mediapipe/tasks/python/vision/image_segmenter.py
@@ -78,16 +78,10 @@ class ImageSegmenterOptions:
       is set to the live stream mode.
   """
 
-  class Activation(enum.Enum):
-    NONE = 0
-    SIGMOID = 1
-    SOFTMAX = 2
-
   base_options: _BaseOptions
   running_mode: _RunningMode = _RunningMode.IMAGE
   output_confidence_masks: bool = True
   output_category_mask: bool = False
-  activation: Optional[Activation] = Activation.NONE
   result_callback: Optional[
       Callable[[ImageSegmenterResult, image_module.Image, int], None]
   ] = None
@@ -99,9 +93,7 @@ class ImageSegmenterOptions:
     base_options_proto.use_stream_mode = (
         False if self.running_mode == _RunningMode.IMAGE else True
     )
-    segmenter_options_proto = _SegmenterOptionsProto(
-        activation=self.activation.value
-    )
+    segmenter_options_proto = _SegmenterOptionsProto()
     return _ImageSegmenterGraphOptionsProto(
         base_options=base_options_proto,
         segmenter_options=segmenter_options_proto,