diff --git a/app/jobs/regular/detect_translate_post.rb b/app/jobs/regular/detect_translate_post.rb
index a5e812d7..7b50a464 100644
--- a/app/jobs/regular/detect_translate_post.rb
+++ b/app/jobs/regular/detect_translate_post.rb
@@ -20,12 +20,15 @@ module Jobs
         end
       end
 
-      begin
-        detected_locale = DiscourseAi::Translation::PostLocaleDetector.detect_locale(post)
-      rescue FinalDestination::SSRFDetector::LookupFailedError
-        # this job is non-critical
-        # the backfill job will handle failures
-        return
+      # the user may fill locale in manually
+      if (detected_locale = post.locale).blank?
+        begin
+          detected_locale = DiscourseAi::Translation::PostLocaleDetector.detect_locale(post)
+        rescue FinalDestination::SSRFDetector::LookupFailedError
+          # this job is non-critical
+          # the backfill job will handle failures
+          return
+        end
       end
 
       locales = SiteSetting.experimental_content_localization_supported_locales.split("|")
@@ -33,6 +36,7 @@ module Jobs
 
       locales.each do |locale|
         next if locale == detected_locale
+        next if post.post_localizations.exists?(locale:)
 
         begin
           DiscourseAi::Translation::PostLocalizer.localize(post, locale)
diff --git a/app/jobs/regular/detect_translate_topic.rb b/app/jobs/regular/detect_translate_topic.rb
index ca5b4901..47ee26d0 100644
--- a/app/jobs/regular/detect_translate_topic.rb
+++ b/app/jobs/regular/detect_translate_topic.rb
@@ -18,12 +18,14 @@ module Jobs
         return if topic.category&.read_restricted?
       end
 
-      begin
-        detected_locale = DiscourseAi::Translation::TopicLocaleDetector.detect_locale(topic)
-      rescue FinalDestination::SSRFDetector::LookupFailedError
-        # this job is non-critical
-        # the backfill job will handle failures
-        return
+      if (detected_locale = topic.locale).blank?
+        begin
+          detected_locale = DiscourseAi::Translation::TopicLocaleDetector.detect_locale(topic)
+        rescue FinalDestination::SSRFDetector::LookupFailedError
+          # this job is non-critical
+          # the backfill job will handle failures
+          return
+        end
       end
 
       locales = SiteSetting.experimental_content_localization_supported_locales.split("|")
@@ -31,6 +33,7 @@ module Jobs
 
       locales.each do |locale|
         next if locale == detected_locale
+        next if topic.topic_localizations.exists?(locale:)
 
         begin
           DiscourseAi::Translation::TopicLocalizer.localize(topic, locale)
diff --git a/spec/jobs/regular/detect_translate_post_spec.rb b/spec/jobs/regular/detect_translate_post_spec.rb
index b3fd6187..21b05a70 100644
--- a/spec/jobs/regular/detect_translate_post_spec.rb
+++ b/spec/jobs/regular/detect_translate_post_spec.rb
@@ -39,6 +39,14 @@ describe Jobs::DetectTranslatePost do
     job.execute({ post_id: post.id })
   end
 
+  it "skips locale detection when post has a locale" do
+    post.update!(locale: "en")
+    DiscourseAi::Translation::PostLocaleDetector.expects(:detect_locale).with(post).never
+    DiscourseAi::Translation::PostLocalizer.expects(:localize).with(post, "ja").once
+
+    job.execute({ post_id: post.id })
+  end
+
   it "skips bot posts" do
     post.update!(user: Discourse.system_user)
     DiscourseAi::Translation::PostLocalizer.expects(:localize).never
@@ -56,16 +64,23 @@ describe Jobs::DetectTranslatePost do
 
   it "skips translating to the post's language" do
     post.update(locale: "en")
-    DiscourseAi::Translation::PostLocaleDetector.expects(:detect_locale).with(post).returns("en")
     DiscourseAi::Translation::PostLocalizer.expects(:localize).with(post, "en").never
     DiscourseAi::Translation::PostLocalizer.expects(:localize).with(post, "ja").once
 
     job.execute({ post_id: post.id })
   end
 
+  it "skips translating if the post is already localized" do
+    post.update(locale: "en")
+    Fabricate(:post_localization, post: post, locale: "ja")
+
+    DiscourseAi::Translation::PostLocalizer.expects(:localize).never
+
+    job.execute({ post_id: post.id })
+  end
+
   it "handles translation errors gracefully" do
     post.update(locale: "en")
-    DiscourseAi::Translation::PostLocaleDetector.expects(:detect_locale).with(post).returns("en")
     DiscourseAi::Translation::PostLocalizer.expects(:localize).raises(
       StandardError.new("API error"),
     )
diff --git a/spec/jobs/regular/detect_translate_topic_spec.rb b/spec/jobs/regular/detect_translate_topic_spec.rb
index 7b397b1b..fca842f1 100644
--- a/spec/jobs/regular/detect_translate_topic_spec.rb
+++ b/spec/jobs/regular/detect_translate_topic_spec.rb
@@ -39,6 +39,14 @@ describe Jobs::DetectTranslateTopic do
     job.execute({ topic_id: topic.id })
   end
 
+  it "skips locale detection when topic has a locale" do
+    topic.update!(locale: "en")
+    DiscourseAi::Translation::TopicLocaleDetector.expects(:detect_locale).with(topic).never
+    DiscourseAi::Translation::TopicLocalizer.expects(:localize).with(topic, "ja").once
+
+    job.execute({ topic_id: topic.id })
+  end
+
   it "skips bot topics" do
     topic.update!(user: Discourse.system_user)
     DiscourseAi::Translation::TopicLocalizer.expects(:localize).never
@@ -56,16 +64,22 @@ describe Jobs::DetectTranslateTopic do
 
   it "skips translating to the topic's language" do
     topic.update(locale: "en")
-    DiscourseAi::Translation::TopicLocaleDetector.expects(:detect_locale).with(topic).returns("en")
     DiscourseAi::Translation::TopicLocalizer.expects(:localize).with(topic, "en").never
     DiscourseAi::Translation::TopicLocalizer.expects(:localize).with(topic, "ja").once
 
     job.execute({ topic_id: topic.id })
   end
 
+  it "skips translating if the topic is already localized" do
+    topic.update(locale: "en")
+    Fabricate(:topic_localization, topic:, locale: "ja")
+    DiscourseAi::Translation::TopicLocalizer.expects(:localize).never
+
+    job.execute({ topic_id: topic.id })
+  end
+
   it "handles translation errors gracefully" do
     topic.update(locale: "en")
-    DiscourseAi::Translation::TopicLocaleDetector.expects(:detect_locale).with(topic).returns("en")
     DiscourseAi::Translation::TopicLocalizer.expects(:localize).raises(
       StandardError.new("API error"),
     )