diff --git a/homeassistant/components/nobo_hub/diagnostics.py b/homeassistant/components/nobo_hub/diagnostics.py
index 62adeddc955c..7916848774cd 100644
--- a/homeassistant/components/nobo_hub/diagnostics.py
+++ b/homeassistant/components/nobo_hub/diagnostics.py
@@ -2,9 +2,9 @@
 
 from typing import Any
 
-from pynobo import ComponentInfo
+from pynobo import ComponentInfo, nobo
 
-from homeassistant.components.diagnostics import async_redact_data
+from homeassistant.components.diagnostics import REDACTED, async_redact_data
 from homeassistant.const import CONF_IP_ADDRESS, CONF_MAC
 from homeassistant.core import HomeAssistant
 
@@ -26,11 +26,12 @@ _MODEL_FIELDS = (
 
 
 def _component_to_dict(component: ComponentInfo) -> dict[str, Any]:
-    formatted = dict(component)
-    if (model := formatted.get("model")) is not None:
-        formatted["model"] = {
-            field: getattr(model, field, None) for field in _MODEL_FIELDS
-        }
+    model = component["model"]
+    formatted: dict[str, Any] = dict(component)
+    formatted["model"] = {field: getattr(model, field, None) for field in _MODEL_FIELDS}
+    if model.type == nobo.Model.UNKNOWN:
+        # Unknown models carry the serial number in the name.
+        formatted["model"]["name"] = REDACTED
     return formatted
 
 
diff --git a/tests/components/nobo_hub/test_diagnostics.py b/tests/components/nobo_hub/test_diagnostics.py
index e4cbebf2b716..2fcdeb95328c 100644
--- a/tests/components/nobo_hub/test_diagnostics.py
+++ b/tests/components/nobo_hub/test_diagnostics.py
@@ -1,7 +1,11 @@
 """Tests for the Nobø Ecohub diagnostics."""
 
+from unittest.mock import MagicMock
+
+from pynobo import nobo as pynobo_nobo
 from syrupy.assertion import SnapshotAssertion
 
+from homeassistant.components.diagnostics import REDACTED
 from homeassistant.core import HomeAssistant
 
 from tests.common import MockConfigEntry
@@ -19,3 +23,31 @@ async def test_entry_diagnostics(
     result = await get_diagnostics_for_config_entry(hass, hass_client, init_integration)
 
     assert result == snapshot
+
+
+async def test_entry_diagnostics_redacts_unknown_model_name(
+    hass: HomeAssistant,
+    hass_client: ClientSessionGenerator,
+    init_integration: MockConfigEntry,
+    mock_nobo_hub: MagicMock,
+) -> None:
+    """An unknown model's name embeds the serial, so it is dropped; model_id is kept."""
+    mock_nobo_hub.components = {
+        "999000012345": {
+            "serial": "999000012345",
+            "name": "Mystery device",
+            "zone_id": "1",
+            "model": pynobo_nobo.Model(
+                model_id="999",
+                type=pynobo_nobo.Model.UNKNOWN,
+                name="Unknown (serial number: 999 000 012 345)",
+            ),
+        },
+    }
+
+    result = await get_diagnostics_for_config_entry(hass, hass_client, init_integration)
+
+    component = result["components"][0]
+    assert component["serial"] == REDACTED
+    assert component["model"]["model_id"] == "999"
+    assert component["model"]["name"] == REDACTED