diff --git a/homeassistant/components/google_generative_ai_conversation/__init__.py b/homeassistant/components/google_generative_ai_conversation/__init__.py
index c6a07a93331..82561d9f75e 100644
--- a/homeassistant/components/google_generative_ai_conversation/__init__.py
+++ b/homeassistant/components/google_generative_ai_conversation/__init__.py
@@ -29,6 +29,7 @@ from homeassistant.helpers import (
     config_validation as cv,
     device_registry as dr,
     entity_registry as er,
+    issue_registry as ir,
 )
 from homeassistant.helpers.typing import ConfigType
 
@@ -70,6 +71,21 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
 
     async def generate_content(call: ServiceCall) -> ServiceResponse:
         """Generate content from text and optionally images."""
+        LOGGER.warning(
+            "Action '%s.%s' is deprecated and will be removed in the 2026.4.0 release. "
+            "Please use the 'ai_task.generate_data' action instead",
+            DOMAIN,
+            SERVICE_GENERATE_CONTENT,
+        )
+        ir.async_create_issue(
+            hass,
+            DOMAIN,
+            "deprecated_generate_content",
+            breaks_in_ha_version="2026.4.0",
+            is_fixable=False,
+            severity=ir.IssueSeverity.WARNING,
+            translation_key="deprecated_generate_content",
+        )
 
         prompt_parts = [call.data[CONF_PROMPT]]
 
diff --git a/homeassistant/components/google_generative_ai_conversation/strings.json b/homeassistant/components/google_generative_ai_conversation/strings.json
index 43008332e68..cc94d7de8fe 100644
--- a/homeassistant/components/google_generative_ai_conversation/strings.json
+++ b/homeassistant/components/google_generative_ai_conversation/strings.json
@@ -150,10 +150,16 @@
       }
     }
   },
+  "issues": {
+    "deprecated_generate_content": {
+      "title": "Deprecated 'generate_content' action",
+      "description": "Action 'google_generative_ai_conversation.generate_content' is deprecated and will be removed in the 2026.4.0 release. Please use the 'ai_task.generate_data' action instead"
+    }
+  },
   "services": {
     "generate_content": {
-      "name": "Generate content",
-      "description": "Generate content from a prompt consisting of text and optionally images",
+      "name": "Generate content (deprecated)",
+      "description": "Generate content from a prompt consisting of text and optionally images (deprecated)",
       "fields": {
         "prompt": {
           "name": "Prompt",