diff --git a/changelogs/fragments/136-docker_swarm_service-fix-idempotence-bug.yml b/changelogs/fragments/136-docker_swarm_service-fix-idempotence-bug.yml
new file mode 100644
index 00000000..2155f222
--- /dev/null
+++ b/changelogs/fragments/136-docker_swarm_service-fix-idempotence-bug.yml
@@ -0,0 +1,2 @@
+bugfixes:
+- "docker_swarm_services - avoid crash during idempotence check if ``published_port`` is not specified (https://github.com/ansible-collections/community.docker/issues/107, https://github.com/ansible-collections/community.docker/pull/136)."
diff --git a/plugins/modules/docker_swarm_service.py b/plugins/modules/docker_swarm_service.py
index d640bf37..2a832312 100644
--- a/plugins/modules/docker_swarm_service.py
+++ b/plugins/modules/docker_swarm_service.py
@@ -917,7 +917,6 @@ EXAMPLES = '''
 
 import shlex
 import time
-import operator
 import traceback
 
 from distutils.version import LooseVersion
@@ -1792,7 +1791,10 @@ class DockerService(DockerBaseClass):
         old_publish = old_publish or []
         if len(self.publish) != len(old_publish):
             return True
-        publish_sorter = operator.itemgetter('published_port', 'target_port', 'protocol')
+
+        def publish_sorter(item):
+            return (item.get('published_port') or 0, item.get('target_port') or 0, item.get('protocol') or '')
+
         publish = sorted(self.publish, key=publish_sorter)
         old_publish = sorted(old_publish, key=publish_sorter)
         for publish_item, old_publish_item in zip(publish, old_publish):
diff --git a/tests/integration/targets/docker_swarm_service/tasks/tests/options.yml b/tests/integration/targets/docker_swarm_service/tasks/tests/options.yml
index df0a5938..ac57a68e 100644
--- a/tests/integration/targets/docker_swarm_service/tasks/tests/options.yml
+++ b/tests/integration/targets/docker_swarm_service/tasks/tests/options.yml
@@ -1526,6 +1526,40 @@
     name: "{{ service_name }}"
   register: publish_8_info
 
+- name: publish (without published_port)
+  docker_swarm_service:
+    name: "{{ service_name }}"
+    image: "{{ docker_test_image_alpine }}"
+    resolve_image: no
+    command: '/bin/sh -v -c "sleep 10m"'
+    publish:
+      - protocol: udp
+        target_port: 60001
+        mode: host
+  register: publish_9
+  ignore_errors: yes
+- name: gather service info
+  docker_swarm_service_info:
+    name: "{{ service_name }}"
+  register: publish_9_info
+
+- name: publish (without published_port, idempotence)
+  docker_swarm_service:
+    name: "{{ service_name }}"
+    image: "{{ docker_test_image_alpine }}"
+    resolve_image: no
+    command: '/bin/sh -v -c "sleep 10m"'
+    publish:
+      - protocol: udp
+        target_port: 60001
+        mode: host
+  register: publish_10
+  ignore_errors: yes
+- name: gather service info
+  docker_swarm_service_info:
+    name: "{{ service_name }}"
+  register: publish_10_info
+
 - name: cleanup
   docker_swarm_service:
     name: "{{ service_name }}"
@@ -1543,6 +1577,8 @@
       - publish_7 is not changed
       - publish_8 is changed
       - (publish_8_info.service.Endpoint.Ports | length) == 2
+      - publish_9 is changed
+      - publish_10 is not changed
   when: docker_api_version is version('1.25', '>=') and docker_py_version is version('3.0.0', '>=')
 - assert:
     that: