diff --git a/homeassistant/components/system_bridge/__init__.py b/homeassistant/components/system_bridge/__init__.py
index c2bf39f51732..034ac51ddfa9 100644
--- a/homeassistant/components/system_bridge/__init__.py
+++ b/homeassistant/components/system_bridge/__init__.py
@@ -2,6 +2,7 @@
 
 import asyncio
 import logging
+from typing import TYPE_CHECKING
 
 from systembridgeconnector.exceptions import (
     AuthenticationException,
@@ -11,7 +12,6 @@ from systembridgeconnector.exceptions import (
 )
 from systembridgeconnector.version import Version
 
-from homeassistant.config_entries import ConfigEntry
 from homeassistant.const import (
     CONF_API_KEY,
     CONF_ENTITY_ID,
@@ -23,7 +23,11 @@ from homeassistant.const import (
 )
 from homeassistant.core import HomeAssistant
 from homeassistant.exceptions import ConfigEntryAuthFailed, ConfigEntryNotReady
-from homeassistant.helpers import config_validation as cv, discovery
+from homeassistant.helpers import (
+    config_validation as cv,
+    discovery,
+    entity_registry as er,
+)
 from homeassistant.helpers.aiohttp_client import async_get_clientsession
 from homeassistant.helpers.issue_registry import IssueSeverity, async_create_issue
 from homeassistant.helpers.typing import ConfigType
@@ -206,7 +210,9 @@ async def async_reload_entry(
     await hass.config_entries.async_reload(entry.entry_id)
 
 
-async def async_migrate_entry(hass: HomeAssistant, config_entry: ConfigEntry) -> bool:
+async def async_migrate_entry(
+    hass: HomeAssistant, config_entry: SystemBridgeConfigEntry
+) -> bool:
     """Migrate old entry."""
     _LOGGER.debug(
         "Migrating from version %s.%s",
@@ -216,6 +222,7 @@ async def async_migrate_entry(hass: HomeAssistant, config_entry: ConfigEntry) ->
 
     if config_entry.minor_version < 2:
         # Migrate to CONF_TOKEN, which was added in 1.2
+
         new_data = dict(config_entry.data)
         new_data.setdefault(CONF_TOKEN, config_entry.data.get(CONF_API_KEY))
 
@@ -231,4 +238,27 @@ async def async_migrate_entry(hass: HomeAssistant, config_entry: ConfigEntry) ->
             config_entry.minor_version,
         )
 
+    if config_entry.minor_version < 3:
+        # Migrate entity unique id
+
+        if TYPE_CHECKING:
+            assert config_entry.unique_id
+
+        ent_reg = er.async_get(hass)
+        for entity_entry in er.async_entries_for_config_entry(
+            ent_reg, config_entry.entry_id
+        ):
+            if not entity_entry.unique_id.startswith(config_entry.data[CONF_HOST]):
+                continue
+
+            ent_reg.async_update_entity(
+                entity_entry.entity_id,
+                new_unique_id=(
+                    config_entry.unique_id
+                    + entity_entry.unique_id[len(config_entry.data[CONF_HOST]) :]
+                ),
+            )
+
+        hass.config_entries.async_update_entry(config_entry, minor_version=3)
+
     return True
diff --git a/homeassistant/components/system_bridge/config_flow.py b/homeassistant/components/system_bridge/config_flow.py
index d2db3a57e978..097c84d1bc4f 100644
--- a/homeassistant/components/system_bridge/config_flow.py
+++ b/homeassistant/components/system_bridge/config_flow.py
@@ -116,7 +116,7 @@ class SystemBridgeConfigFlow(
     """Handle a config flow for System Bridge."""
 
     VERSION = 1
-    MINOR_VERSION = 2
+    MINOR_VERSION = 3
 
     _name: str
 
diff --git a/homeassistant/components/system_bridge/entity.py b/homeassistant/components/system_bridge/entity.py
index 6c9ffd03a00c..f2b89789e603 100644
--- a/homeassistant/components/system_bridge/entity.py
+++ b/homeassistant/components/system_bridge/entity.py
@@ -1,7 +1,5 @@
 """Base entity for the system bridge integration."""
 
-from typing import override
-
 from homeassistant.helpers import device_registry as dr
 from homeassistant.helpers.device_registry import DeviceInfo
 from homeassistant.helpers.update_coordinator import CoordinatorEntity
@@ -25,7 +23,11 @@ class SystemBridgeEntity(CoordinatorEntity[SystemBridgeDataUpdateCoordinator]):
         super().__init__(coordinator)
 
         self._hostname = coordinator.data.system.hostname
-        self._key = f"{self._hostname}_{key}" if key is not None else self._hostname
+        self._attr_unique_id = (
+            f"{coordinator.data.system.uuid}_{key}"
+            if key is not None
+            else coordinator.data.system.uuid
+        )
         self._configuration_url = (
             f"http://{self._hostname}:{api_port}/app/settings.html"
         )
@@ -33,17 +35,7 @@ class SystemBridgeEntity(CoordinatorEntity[SystemBridgeDataUpdateCoordinator]):
         self._uuid = coordinator.data.system.uuid
         self._version = coordinator.data.system.version
 
-    @property
-    @override
-    def unique_id(self) -> str:
-        """Return the unique ID for this entity."""
-        return self._key
-
-    @property
-    @override
-    def device_info(self) -> DeviceInfo:
-        """Return device information about this System Bridge instance."""
-        return DeviceInfo(
+        self._attr_device_info = DeviceInfo(
             configuration_url=self._configuration_url,
             connections={(dr.CONNECTION_NETWORK_MAC, self._mac_address)},
             identifiers={(DOMAIN, self._uuid)},
diff --git a/tests/components/system_bridge/snapshots/test_binary_sensor.ambr b/tests/components/system_bridge/snapshots/test_binary_sensor.ambr
index 464440261a0f..8a5a47702d45 100644
--- a/tests/components/system_bridge/snapshots/test_binary_sensor.ambr
+++ b/tests/components/system_bridge/snapshots/test_binary_sensor.ambr
@@ -32,7 +32,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'camera_in_use',
-    'unique_id': 'hostname_camera_in_use',
+    'unique_id': 'uuid_camera_in_use',
     'unit_of_measurement': None,
   })
 # ---
@@ -82,7 +82,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': None,
-    'unique_id': 'hostname_battery_is_charging',
+    'unique_id': 'uuid_battery_is_charging',
     'unit_of_measurement': None,
   })
 # ---
@@ -133,7 +133,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'pending_reboot',
-    'unique_id': 'hostname_pending_reboot',
+    'unique_id': 'uuid_pending_reboot',
     'unit_of_measurement': None,
   })
 # ---
@@ -183,7 +183,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': None,
-    'unique_id': 'hostname_version_available',
+    'unique_id': 'uuid_version_available',
     'unit_of_measurement': None,
   })
 # ---
diff --git a/tests/components/system_bridge/snapshots/test_notify.ambr b/tests/components/system_bridge/snapshots/test_notify.ambr
index 4e13f5f7fd26..cf70f4a8a2de 100644
--- a/tests/components/system_bridge/snapshots/test_notify.ambr
+++ b/tests/components/system_bridge/snapshots/test_notify.ambr
@@ -32,7 +32,7 @@
     'suggested_object_id': None,
     'supported_features': <NotifyEntityFeature: 1>,
     'translation_key': None,
-    'unique_id': 'hostname',
+    'unique_id': 'uuid',
     'unit_of_measurement': None,
   })
 # ---
diff --git a/tests/components/system_bridge/snapshots/test_sensor.ambr b/tests/components/system_bridge/snapshots/test_sensor.ambr
index 5c54045ab793..9079fb1fcd5c 100644
--- a/tests/components/system_bridge/snapshots/test_sensor.ambr
+++ b/tests/components/system_bridge/snapshots/test_sensor.ambr
@@ -37,7 +37,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': None,
-    'unique_id': 'hostname_battery',
+    'unique_id': 'uuid_battery',
     'unit_of_measurement': '%',
   })
 # ---
@@ -90,7 +90,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'battery_time_remaining',
-    'unique_id': 'hostname_battery_time_remaining',
+    'unique_id': 'uuid_battery_time_remaining',
     'unit_of_measurement': None,
   })
 # ---
@@ -141,7 +141,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'boot_time',
-    'unique_id': 'hostname_boot_time',
+    'unique_id': 'uuid_boot_time',
     'unit_of_measurement': None,
   })
 # ---
@@ -197,7 +197,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'cpu_power_core',
-    'unique_id': 'hostname_cpu_power_core_0',
+    'unique_id': 'uuid_cpu_power_core_0',
     'unit_of_measurement': <UnitOfPower.WATT: 'W'>,
   })
 # ---
@@ -254,7 +254,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'cpu_power_package',
-    'unique_id': 'hostname_cpu_power_package',
+    'unique_id': 'uuid_cpu_power_package',
     'unit_of_measurement': <UnitOfPower.WATT: 'W'>,
   })
 # ---
@@ -311,7 +311,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'cpu_speed',
-    'unique_id': 'hostname_cpu_speed',
+    'unique_id': 'uuid_cpu_speed',
     'unit_of_measurement': <UnitOfFrequency.GIGAHERTZ: 'GHz'>,
   })
 # ---
@@ -369,7 +369,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'cpu_temperature',
-    'unique_id': 'hostname_cpu_temperature',
+    'unique_id': 'uuid_cpu_temperature',
     'unit_of_measurement': <UnitOfTemperature.CELSIUS: '°C'>,
   })
 # ---
@@ -427,7 +427,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'cpu_voltage',
-    'unique_id': 'hostname_cpu_voltage',
+    'unique_id': 'uuid_cpu_voltage',
     'unit_of_measurement': <UnitOfElectricPotential.VOLT: 'V'>,
   })
 # ---
@@ -485,7 +485,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'display_refresh_rate',
-    'unique_id': 'hostname_display_abc123_refresh_rate',
+    'unique_id': 'uuid_display_abc123_refresh_rate',
     'unit_of_measurement': <UnitOfFrequency.HERTZ: 'Hz'>,
   })
 # ---
@@ -540,7 +540,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'display_resolution_x',
-    'unique_id': 'hostname_display_abc123_resolution_x',
+    'unique_id': 'uuid_display_abc123_resolution_x',
     'unit_of_measurement': 'px',
   })
 # ---
@@ -594,7 +594,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'display_resolution_y',
-    'unique_id': 'hostname_display_abc123_resolution_y',
+    'unique_id': 'uuid_display_abc123_resolution_y',
     'unit_of_measurement': 'px',
   })
 # ---
@@ -648,7 +648,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'displays_connected',
-    'unique_id': 'hostname_displays_connected',
+    'unique_id': 'uuid_displays_connected',
     'unit_of_measurement': None,
   })
 # ---
@@ -699,7 +699,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'kernel',
-    'unique_id': 'hostname_kernel',
+    'unique_id': 'uuid_kernel',
     'unit_of_measurement': None,
   })
 # ---
@@ -749,7 +749,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'version_latest',
-    'unique_id': 'hostname_version_latest',
+    'unique_id': 'uuid_version_latest',
     'unit_of_measurement': None,
   })
 # ---
@@ -804,7 +804,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'load',
-    'unique_id': 'hostname_processes_load',
+    'unique_id': 'uuid_processes_load',
     'unit_of_measurement': '%',
   })
 # ---
@@ -861,7 +861,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'processes_load_cpu',
-    'unique_id': 'hostname_processes_load_cpu_0',
+    'unique_id': 'uuid_processes_load_cpu_0',
     'unit_of_measurement': '%',
   })
 # ---
@@ -918,7 +918,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'memory_free',
-    'unique_id': 'hostname_memory_free',
+    'unique_id': 'uuid_memory_free',
     'unit_of_measurement': <UnitOfInformation.GIGABYTES: 'GB'>,
   })
 # ---
@@ -976,7 +976,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'memory_used_percentage',
-    'unique_id': 'hostname_memory_used_percentage',
+    'unique_id': 'uuid_memory_used_percentage',
     'unit_of_measurement': '%',
   })
 # ---
@@ -1033,7 +1033,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'memory_used',
-    'unique_id': 'hostname_memory_used',
+    'unique_id': 'uuid_memory_used',
     'unit_of_measurement': <UnitOfInformation.GIGABYTES: 'GB'>,
   })
 # ---
@@ -1091,7 +1091,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'space_used',
-    'unique_id': 'hostname_filesystem_mountpoint',
+    'unique_id': 'uuid_filesystem_mountpoint',
     'unit_of_measurement': '%',
   })
 # ---
@@ -1148,7 +1148,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_core_clock_speed',
-    'unique_id': 'hostname_gpu_abc123_core_clock_speed',
+    'unique_id': 'uuid_gpu_abc123_core_clock_speed',
     'unit_of_measurement': <UnitOfFrequency.MEGAHERTZ: 'MHz'>,
   })
 # ---
@@ -1203,7 +1203,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_fan_speed',
-    'unique_id': 'hostname_gpu_abc123_fan_speed',
+    'unique_id': 'uuid_gpu_abc123_fan_speed',
     'unit_of_measurement': 'rpm',
   })
 # ---
@@ -1260,7 +1260,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_memory_clock_speed',
-    'unique_id': 'hostname_gpu_abc123_memory_clock_speed',
+    'unique_id': 'uuid_gpu_abc123_memory_clock_speed',
     'unit_of_measurement': <UnitOfFrequency.MEGAHERTZ: 'MHz'>,
   })
 # ---
@@ -1318,7 +1318,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_memory_free',
-    'unique_id': 'hostname_gpu_abc123_memory_free',
+    'unique_id': 'uuid_gpu_abc123_memory_free',
     'unit_of_measurement': <UnitOfInformation.MEGABYTES: 'MB'>,
   })
 # ---
@@ -1376,7 +1376,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_memory_used_percentage',
-    'unique_id': 'hostname_gpu_abc123_memory_used_percentage',
+    'unique_id': 'uuid_gpu_abc123_memory_used_percentage',
     'unit_of_measurement': '%',
   })
 # ---
@@ -1433,7 +1433,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_memory_used',
-    'unique_id': 'hostname_gpu_abc123_memory_used',
+    'unique_id': 'uuid_gpu_abc123_memory_used',
     'unit_of_measurement': <UnitOfInformation.MEGABYTES: 'MB'>,
   })
 # ---
@@ -1488,7 +1488,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_power_usage',
-    'unique_id': 'hostname_gpu_abc123_power_usage',
+    'unique_id': 'uuid_gpu_abc123_power_usage',
     'unit_of_measurement': <UnitOfPower.WATT: 'W'>,
   })
 # ---
@@ -1545,7 +1545,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_temperature',
-    'unique_id': 'hostname_gpu_abc123_temperature',
+    'unique_id': 'uuid_gpu_abc123_temperature',
     'unit_of_measurement': <UnitOfTemperature.CELSIUS: '°C'>,
   })
 # ---
@@ -1603,7 +1603,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'gpu_usage_percentage',
-    'unique_id': 'hostname_gpu_abc123_usage_percentage',
+    'unique_id': 'uuid_gpu_abc123_usage_percentage',
     'unit_of_measurement': '%',
   })
 # ---
@@ -1655,7 +1655,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'os',
-    'unique_id': 'hostname_os',
+    'unique_id': 'uuid_os',
     'unit_of_measurement': None,
   })
 # ---
@@ -1710,7 +1710,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'power_usage',
-    'unique_id': 'hostname_power_usage',
+    'unique_id': 'uuid_power_usage',
     'unit_of_measurement': <UnitOfPower.WATT: 'W'>,
   })
 # ---
@@ -1765,7 +1765,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'processes',
-    'unique_id': 'hostname_processes_count',
+    'unique_id': 'uuid_processes_count',
     'unit_of_measurement': None,
   })
 # ---
@@ -1816,7 +1816,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': 'version',
-    'unique_id': 'hostname_version',
+    'unique_id': 'uuid_version',
     'unit_of_measurement': None,
   })
 # ---
diff --git a/tests/components/system_bridge/snapshots/test_update.ambr b/tests/components/system_bridge/snapshots/test_update.ambr
index c61740232ecd..bb36270eb6d8 100644
--- a/tests/components/system_bridge/snapshots/test_update.ambr
+++ b/tests/components/system_bridge/snapshots/test_update.ambr
@@ -32,7 +32,7 @@
     'suggested_object_id': None,
     'supported_features': 0,
     'translation_key': None,
-    'unique_id': 'hostname_update',
+    'unique_id': 'uuid_update',
     'unit_of_measurement': None,
   })
 # ---
diff --git a/tests/components/system_bridge/test_config_flow.py b/tests/components/system_bridge/test_config_flow.py
index ada44de2d12b..1367744c02f0 100644
--- a/tests/components/system_bridge/test_config_flow.py
+++ b/tests/components/system_bridge/test_config_flow.py
@@ -375,14 +375,13 @@ async def test_reauth_connection_closed_error(hass: HomeAssistant) -> None:
     assert result2["errors"] == {"base": "cannot_connect"}
 
 
-async def test_reauth_flow(hass: HomeAssistant) -> None:
+async def test_reauth_flow(
+    hass: HomeAssistant, mock_config_entry: MockConfigEntry
+) -> None:
     """Test reauth flow."""
-    mock_config = MockConfigEntry(
-        domain=DOMAIN, unique_id=FIXTURE_UUID, data=FIXTURE_USER_INPUT
-    )
-    mock_config.add_to_hass(hass)
+    mock_config_entry.add_to_hass(hass)
 
-    result = await mock_config.start_reauth_flow(hass)
+    result = await mock_config_entry.start_reauth_flow(hass)
 
     assert result["type"] is FlowResultType.FORM
     assert result["step_id"] == "authenticate"
diff --git a/tests/components/system_bridge/test_init.py b/tests/components/system_bridge/test_init.py
index a129818afe11..72296da8bd41 100644
--- a/tests/components/system_bridge/test_init.py
+++ b/tests/components/system_bridge/test_init.py
@@ -9,6 +9,7 @@ from homeassistant.components.system_bridge.const import DOMAIN
 from homeassistant.config_entries import ConfigEntryState
 from homeassistant.const import CONF_API_KEY, CONF_HOST, CONF_PORT, CONF_TOKEN
 from homeassistant.core import HomeAssistant
+from homeassistant.helpers import entity_registry as er
 
 from . import FIXTURE_USER_INPUT, FIXTURE_UUID
 
@@ -68,6 +69,59 @@ async def test_migration_minor_1_to_2(hass: HomeAssistant) -> None:
     assert config_entry.state is ConfigEntryState.LOADED
 
 
+@pytest.mark.usefixtures("mock_version", "mock_websocket_client")
+async def test_migration_minor_2_to_3(
+    hass: HomeAssistant,
+    entity_registry: er.EntityRegistry,
+) -> None:
+    """Test migration of entity unique ids."""
+    config_entry = MockConfigEntry(
+        domain=DOMAIN,
+        unique_id=FIXTURE_UUID,
+        data={
+            CONF_TOKEN: FIXTURE_USER_INPUT[CONF_TOKEN],
+            CONF_HOST: "hostname",
+            CONF_PORT: FIXTURE_USER_INPUT[CONF_PORT],
+        },
+        version=1,
+        minor_version=2,
+    )
+
+    config_entry.add_to_hass(hass)
+    assert config_entry.minor_version == 2
+
+    sensor = entity_registry.async_get_or_create(
+        domain="sensor",
+        platform=DOMAIN,
+        unique_id="hostname_cpu_speed",
+        config_entry=config_entry,
+        original_name="hostname CPU speed",
+    )
+
+    notifier = entity_registry.async_get_or_create(
+        domain="notify",
+        platform=DOMAIN,
+        unique_id="hostname",
+        config_entry=config_entry,
+        original_name="hostname",
+    )
+
+    await hass.config_entries.async_setup(config_entry.entry_id)
+    await hass.async_block_till_done()
+
+    assert config_entry.version == 1
+    assert config_entry.minor_version == 3
+
+    assert (
+        entity_registry.async_get(sensor.entity_id).unique_id
+        == f"{FIXTURE_UUID}_cpu_speed"
+    )
+
+    assert entity_registry.async_get(notifier.entity_id).unique_id == FIXTURE_UUID
+
+    assert config_entry.state is ConfigEntryState.LOADED
+
+
 async def test_migration_minor_future_version(hass: HomeAssistant) -> None:
     """Test migration."""
     config_entry_data = {