diff --git a/homeassistant/components/nexia/__init__.py b/homeassistant/components/nexia/__init__.py
index 8d0d509f8a2b..ace24d65d8bc 100644
--- a/homeassistant/components/nexia/__init__.py
+++ b/homeassistant/components/nexia/__init__.py
@@ -61,6 +61,16 @@ async def async_setup_entry(hass: HomeAssistant, entry: NexiaConfigEntry) -> boo
     coordinator = NexiaDataUpdateCoordinator(hass, entry, nexia_home)
     await coordinator.async_config_entry_first_refresh()
     entry.runtime_data = coordinator
+
+    # Register thermostat devices before forwarding platforms so zone sub-devices
+    # can resolve their via_device_id regardless of platform setup order.
+    device_registry = dr.async_get(hass)
+    for thermostat_id in nexia_home.get_thermostat_ids():
+        device_registry.async_get_or_create(
+            config_entry_id=entry.entry_id,
+            identifiers={(DOMAIN, thermostat_id)},  # type: ignore[arg-type] # until fix issue #139773
+        )
+
     await hass.config_entries.async_forward_entry_setups(entry, PLATFORMS)
 
     return True
diff --git a/homeassistant/components/nexia/entity.py b/homeassistant/components/nexia/entity.py
index 04af39d6f84e..068419f68b52 100644
--- a/homeassistant/components/nexia/entity.py
+++ b/homeassistant/components/nexia/entity.py
@@ -5,12 +5,8 @@ from typing import TYPE_CHECKING, override
 from nexia.thermostat import NexiaThermostat
 from nexia.zone import NexiaThermostatZone
 
-from homeassistant.const import (
-    ATTR_IDENTIFIERS,
-    ATTR_NAME,
-    ATTR_SUGGESTED_AREA,
-    ATTR_VIA_DEVICE,
-)
+from homeassistant.const import ATTR_IDENTIFIERS, ATTR_NAME, ATTR_SUGGESTED_AREA
+from homeassistant.helpers import device_registry as dr
 from homeassistant.helpers.device_registry import DeviceInfo
 from homeassistant.helpers.dispatcher import (
     async_dispatcher_connect,
@@ -113,7 +109,11 @@ class NexiaThermostatZoneEntity(NexiaThermostatEntity):
             ATTR_IDENTIFIERS: {(DOMAIN, zone.zone_id)},  # type: ignore[arg-type] # until fix issue #139773
             ATTR_NAME: zone_name,
             ATTR_SUGGESTED_AREA: zone_name,
-            ATTR_VIA_DEVICE: (DOMAIN, zone.thermostat.thermostat_id),  # type: ignore[typeddict-item] # until fix issue #139773
+            "via_device_id": dr.async_get_device_id_by_identifier(
+                self.coordinator.hass,
+                (DOMAIN, zone.thermostat.thermostat_id),  # type: ignore[arg-type] # until fix issue #139773
+                config_entry_id=self.coordinator.config_entry.entry_id,
+            ),
         }
         self._zone_signal = f"{SIGNAL_ZONE_UPDATE}-{zone.zone_id}"
 
diff --git a/tests/components/nexia/test_init.py b/tests/components/nexia/test_init.py
index 4546cd71e6a6..ef8734075c59 100644
--- a/tests/components/nexia/test_init.py
+++ b/tests/components/nexia/test_init.py
@@ -76,3 +76,25 @@ async def test_migrate_entry_minor_version_1_2(hass: HomeAssistant) -> None:
         assert entry.version == 1
         assert entry.minor_version == 2
         assert entry.unique_id == "123456"
+
+
+async def test_device_via_device_links(
+    hass: HomeAssistant,
+    patch_nexia_home: NexiaHome,
+    device_registry: dr.DeviceRegistry,
+) -> None:
+    """Test a zone device links to its thermostat via via_device_id."""
+    config_entry = await setup_integration(hass, patch_nexia_home)
+
+    thermostat_device = device_registry.async_get_device_by_identifier(
+        (DOMAIN, 2000000),  # type: ignore[arg-type] # until fix issue #139773
+        config_entry.entry_id,
+    )
+    assert thermostat_device is not None
+
+    zone_device = device_registry.async_get_device_by_identifier(
+        (DOMAIN, 100),  # type: ignore[arg-type] # until fix issue #139773
+        config_entry.entry_id,
+    )
+    assert zone_device is not None
+    assert zone_device.via_device_id == thermostat_device.id