diff --git a/doc/source/serve/monitoring.md b/doc/source/serve/monitoring.md
index 97f1a0ada4dc..a3d1053f20de 100644
--- a/doc/source/serve/monitoring.md
+++ b/doc/source/serve/monitoring.md
@@ -718,6 +718,11 @@ These metrics track replica health, restarts, and lifecycle timing.
 These lifecycle **histograms** use `deployment` and `application` labels only—no `replica` label—so Prometheus cardinality stays manageable at scale.
 :::
 
+By default, replica lifecycle metrics include source identifiers such as
+`replica` where applicable. For large deployments, set
+`RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS=0` to drop those
+source-level high-cardinality tags while retaining `deployment` and `application`.
+
 | Metric | Type | Tags | Description |
 |--------|------|------|-------------|
 | `ray_serve_deployment_replica_healthy` | Gauge | `deployment`, `replica`, `application` | Health status of the replica: `1` = healthy, `0` = unhealthy. |
@@ -733,6 +738,11 @@ These lifecycle **histograms** use `deployment` and `application` labels only—
 
 These metrics provide visibility into autoscaling behavior and help debug scaling issues.
 
+By default, autoscaling metrics include source identifiers such as `handle` and
+`replica` where applicable. For large deployments, set
+`RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS=0` to drop those
+source-level high-cardinality tags while retaining `deployment` and `application`.
+
 | Metric | Type | Tags | Description |
 |--------|------|------|-------------|
 | `ray_serve_autoscaling_target_replicas` | Gauge | `deployment`, `application` | Target number of replicas the autoscaler is trying to reach. Compare with actual replicas to identify scaling lag. |
diff --git a/python/ray/serve/_private/constants.py b/python/ray/serve/_private/constants.py
index 73f404f087e5..084a35a42774 100644
--- a/python/ray/serve/_private/constants.py
+++ b/python/ray/serve/_private/constants.py
@@ -928,6 +928,14 @@
 RAY_SERVE_AGGREGATE_METRICS_AT_CONTROLLER = get_env_bool(
     "RAY_SERVE_AGGREGATE_METRICS_AT_CONTROLLER", "0"
 )
+
+# Feature flag to include high-cardinality source tags on Serve controller metrics.
+# Disable this to keep deployment/application tags while dropping source identifiers
+# like replica IDs and handle IDs from controller-emitted metrics.
+RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS = get_env_bool(
+    "RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS", "1"
+)
+
 # Feature flag to use compact (low-cardinality) namespace tags on long poll metrics.
 # When enabled, metric tags use only the LongPollNamespace enum name
 # (e.g., "DEPLOYMENT_CONFIG") instead of the full key string which includes
diff --git a/python/ray/serve/_private/controller.py b/python/ray/serve/_private/controller.py
index 4239d5bdaae2..408108ca74f1 100644
--- a/python/ray/serve/_private/controller.py
+++ b/python/ray/serve/_private/controller.py
@@ -36,6 +36,7 @@
 from ray.serve._private.constants import (
     CONTROL_LOOP_INTERVAL_S,
     RAY_SERVE_CONTROLLER_CALLBACK_IMPORT_PATH,
+    RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS,
     RAY_SERVE_ENABLE_DIRECT_INGRESS,
     RAY_SERVE_ENABLE_HA_PROXY,
     RAY_SERVE_LOG_TO_STDERR,
@@ -114,6 +115,33 @@
 
 logger = logging.getLogger(SERVE_LOGGER_NAME)
 
+_AUTOSCALING_METRICS_DELAY_BASE_TAG_KEYS = ("deployment", "application")
+
+
+def _get_autoscaling_metrics_delay_tag_keys(
+    high_cardinality_tag_keys: Tuple[str, ...],
+) -> Tuple[str, ...]:
+    """Return tag keys for controller autoscaling metrics delay gauges."""
+    if RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS:
+        return _AUTOSCALING_METRICS_DELAY_BASE_TAG_KEYS + high_cardinality_tag_keys
+    return _AUTOSCALING_METRICS_DELAY_BASE_TAG_KEYS
+
+
+def _get_autoscaling_metrics_delay_tags(
+    deployment_id: DeploymentID,
+    high_cardinality_tag_key: str,
+    high_cardinality_tag_value: str,
+) -> Dict[str, str]:
+    """Return tags for controller autoscaling metrics delay gauge updates."""
+    tags = {
+        "deployment": deployment_id.name,
+        "application": deployment_id.app_name,
+    }
+    if RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS:
+        tags[high_cardinality_tag_key] = high_cardinality_tag_value
+    return tags
+
+
 # Used for testing purposes only. If this is set, the controller will crash
 # after writing each checkpoint with the specified probability.
 _CRASH_AFTER_CHECKPOINT_PROBABILITY = 0
@@ -358,11 +386,11 @@ def record_autoscaling_metrics_from_replica(
         # Record the metrics delay for observability
         self.replica_metrics_delay_gauge.set(
             latency_ms,
-            tags={
-                "deployment": replica_metric_report.replica_id.deployment_id.name,
-                "application": replica_metric_report.replica_id.deployment_id.app_name,
-                "replica": replica_metric_report.replica_id.unique_id,
-            },
+            tags=_get_autoscaling_metrics_delay_tags(
+                replica_metric_report.replica_id.deployment_id,
+                "replica",
+                replica_metric_report.replica_id.unique_id,
+            ),
         )
         # Track in health metrics
         self._health_metrics_tracker.record_replica_metrics_delay(latency_ms)
@@ -380,11 +408,11 @@ def record_autoscaling_metrics_from_handle(
         # Record the metrics delay for observability
         self.handle_metrics_delay_gauge.set(
             latency_ms,
-            tags={
-                "deployment": handle_metric_report.deployment_id.name,
-                "application": handle_metric_report.deployment_id.app_name,
-                "handle": handle_metric_report.handle_id,
-            },
+            tags=_get_autoscaling_metrics_delay_tags(
+                handle_metric_report.deployment_id,
+                "handle",
+                handle_metric_report.handle_id,
+            ),
         )
         # Track in health metrics
         self._health_metrics_tracker.record_handle_metrics_delay(latency_ms)
@@ -742,7 +770,7 @@ def _create_control_loop_metrics(self):
                 "Time taken for the replica metrics to be reported to the controller. "
                 "High values may indicate a busy controller."
             ),
-            tag_keys=("deployment", "application", "replica"),
+            tag_keys=_get_autoscaling_metrics_delay_tag_keys(("replica",)),
         )
         self.handle_metrics_delay_gauge = metrics.Gauge(
             "serve_autoscaling_handle_metrics_delay_ms",
@@ -750,7 +778,7 @@ def _create_control_loop_metrics(self):
                 "Time taken for the handle metrics to be reported to the controller. "
                 "High values may indicate a busy controller."
             ),
-            tag_keys=("deployment", "application", "handle"),
+            tag_keys=_get_autoscaling_metrics_delay_tag_keys(("handle",)),
         )
         self.async_inference_task_queue_metrics_delay_gauge = metrics.Gauge(
             "serve_autoscaling_async_inference_task_queue_metrics_delay_ms",
@@ -758,7 +786,7 @@ def _create_control_loop_metrics(self):
                 "Time taken for the async inference task queue metrics to be reported "
                 "to the controller. High values may indicate a busy controller."
             ),
-            tag_keys=("deployment", "application"),
+            tag_keys=_AUTOSCALING_METRICS_DELAY_BASE_TAG_KEYS,
         )
 
     def _recover_state_from_checkpoint(self):
diff --git a/python/ray/serve/_private/deployment_state.py b/python/ray/serve/_private/deployment_state.py
index 856e8183ebe0..6284574fe622 100644
--- a/python/ray/serve/_private/deployment_state.py
+++ b/python/ray/serve/_private/deployment_state.py
@@ -49,6 +49,7 @@
     DEPLOYMENT_ACTOR_HEALTH_CHECK_TIMEOUT_S,
     DEPLOYMENT_ACTOR_HEALTH_CHECK_UNHEALTHY_THRESHOLD,
     MAX_PER_REPLICA_RETRY_COUNT,
+    RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS,
     RAY_SERVE_DIRECT_INGRESS_MIN_DRAINING_PERIOD_S,
     RAY_SERVE_ENABLE_DIRECT_INGRESS,
     RAY_SERVE_ENABLE_TASK_EVENTS,
@@ -104,6 +105,23 @@
 
 logger = logging.getLogger(SERVE_LOGGER_NAME)
 
+_REPLICA_LIFECYCLE_METRIC_BASE_TAG_KEYS = ("deployment", "application")
+
+
+def _get_replica_lifecycle_metric_tag_keys() -> Tuple[str, ...]:
+    if RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS:
+        return ("deployment", "replica", "application")
+    return _REPLICA_LIFECYCLE_METRIC_BASE_TAG_KEYS
+
+
+def _get_replica_lifecycle_metric_tags(
+    replica_unique_id: str,
+) -> Optional[Dict[str, str]]:
+    if RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS:
+        return {"replica": replica_unique_id}
+    return None
+
+
 _RESERVED_INTERNAL_DEPLOYMENT_CONTEXT_ENV_VARS = {
     RAY_SERVE_INTERNAL_DEPLOYMENT_APP_NAME_ENV_VAR,
     RAY_SERVE_INTERNAL_DEPLOYMENT_NAME_ENV_VAR,
@@ -2869,7 +2887,7 @@ def __init__(
                 "Tracks whether this deployment replica is healthy. 1 means "
                 "healthy, 0 means unhealthy."
             ),
-            tag_keys=("deployment", "replica", "application"),
+            tag_keys=_get_replica_lifecycle_metric_tag_keys(),
         )
         self.health_check_gauge.set_default_tags(
             {"deployment": self._id.name, "application": self._id.app_name}
@@ -2924,7 +2942,7 @@ def __init__(
         self.health_check_failures_counter = metrics.Counter(
             "serve_health_check_failures_total",
             description=("Count of failed health checks."),
-            tag_keys=("deployment", "replica", "application"),
+            tag_keys=_get_replica_lifecycle_metric_tag_keys(),
         )
         self.health_check_failures_counter.set_default_tags(
             {"deployment": self._id.name, "application": self._id.app_name}
@@ -4331,7 +4349,10 @@ def _set_health_gauge(self, replica_unique_id: str, value: int) -> None:
             and (now - cached[1]) < RAY_SERVE_STATUS_GAUGE_REPORT_INTERVAL_S
         ):
             return
-        self.health_check_gauge.set(value, tags={"replica": replica_unique_id})
+        self.health_check_gauge.set(
+            value,
+            tags=_get_replica_lifecycle_metric_tags(replica_unique_id),
+        )
         self._health_gauge_cache[replica_unique_id] = (value, now)
 
     def _register_gang_replica(self, replica_id: ReplicaID, gang_id: str) -> None:
@@ -4498,7 +4519,9 @@ def check_and_update_replicas(self):
                 )
             if replica.last_health_check_failed:
                 self.health_check_failures_counter.inc(
-                    tags={"replica": replica.replica_id.unique_id}
+                    tags=_get_replica_lifecycle_metric_tags(
+                        replica.replica_id.unique_id
+                    )
                 )
 
             if is_healthy:
diff --git a/python/ray/serve/_private/replica.py b/python/ray/serve/_private/replica.py
index b7232b0527b4..eb2e04006756 100644
--- a/python/ray/serve/_private/replica.py
+++ b/python/ray/serve/_private/replica.py
@@ -63,6 +63,7 @@
     HEALTHY_MESSAGE,
     RAY_SERVE_AUTOSCALING_METRIC_RECORD_INTERVAL_FACTOR,
     RAY_SERVE_COLLECT_AUTOSCALING_METRICS_ON_HANDLE,
+    RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS,
     RAY_SERVE_DIRECT_INGRESS_MIN_DRAINING_PERIOD_S,
     RAY_SERVE_DIRECT_INGRESS_PORT_RETRY_COUNT,
     RAY_SERVE_ENABLE_DIRECT_INGRESS,
@@ -190,6 +191,30 @@
 
 logger = logging.getLogger(SERVE_LOGGER_NAME)
 
+_REPLICA_METRIC_BASE_TAG_KEYS = ("deployment", "application")
+
+
+def _get_replica_metric_default_tag_keys(
+    additional_tag_keys: Tuple[str, ...] = tuple(),
+) -> Tuple[str, ...]:
+    if RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS:
+        return ("deployment", "replica", "application") + additional_tag_keys
+    return _REPLICA_METRIC_BASE_TAG_KEYS + additional_tag_keys
+
+
+def _get_replica_metric_default_tags(
+    deployment_id: DeploymentID,
+    replica_unique_id: str,
+) -> Dict[str, str]:
+    tags = {
+        "deployment": deployment_id.name,
+        "application": deployment_id.app_name,
+    }
+    if RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS:
+        tags["replica"] = replica_unique_id
+    return tags
+
+
 SERVE_BUILD_ASGI_APP_METHOD = "__serve_build_asgi_app__"
 
 
@@ -363,11 +388,18 @@ def __init__(
         self._cached_metrics_interval_s = RAY_SERVE_METRICS_EXPORT_INTERVAL_MS / 1000
 
         # Request counter (only set on replica startup).
-        self._restart_counter = metrics.Counter(
+        self._restart_counter = ray_metrics.Counter(
             "serve_deployment_replica_starts",
             description=(
                 "The number of times this replica has been restarted due to failure."
             ),
+            tag_keys=_get_replica_metric_default_tag_keys(),
+        )
+        self._restart_counter.set_default_tags(
+            _get_replica_metric_default_tags(
+                self._deployment_id,
+                self._replica_id.unique_id,
+            )
         )
         self._restart_counter.inc()
 
@@ -426,19 +458,32 @@ def __init__(
             description="The current number of queries being processed.",
         )
 
-        self.record_autoscaling_stats_failed_counter = metrics.Counter(
+        self.record_autoscaling_stats_failed_counter = ray_metrics.Counter(
             "serve_record_autoscaling_stats_failed",
-            tag_keys=("exception_name",),
+            tag_keys=_get_replica_metric_default_tag_keys(("exception_name",)),
             description="The number of errored record_autoscaling_stats invocations.",
         )
+        self.record_autoscaling_stats_failed_counter.set_default_tags(
+            _get_replica_metric_default_tags(
+                self._deployment_id,
+                self._replica_id.unique_id,
+            )
+        )
 
-        self.user_autoscaling_stats_latency_tracker = metrics.Histogram(
+        self.user_autoscaling_stats_latency_tracker = ray_metrics.Histogram(
             "serve_user_autoscaling_stats_latency_ms",
             description=(
                 "Time taken to execute the user-defined autoscaling stats function "
                 "in milliseconds."
             ),
             boundaries=REQUEST_LATENCY_BUCKETS_MS,
+            tag_keys=_get_replica_metric_default_tag_keys(),
+        )
+        self.user_autoscaling_stats_latency_tracker.set_default_tags(
+            _get_replica_metric_default_tags(
+                self._deployment_id,
+                self._replica_id.unique_id,
+            )
         )
 
         # Replica utilization tracking with rolling window.
diff --git a/python/ray/serve/tests/unit/test_controller.py b/python/ray/serve/tests/unit/test_controller.py
index 1db5ac20bff1..4b4d5071a193 100644
--- a/python/ray/serve/tests/unit/test_controller.py
+++ b/python/ray/serve/tests/unit/test_controller.py
@@ -2,8 +2,10 @@
 
 import pytest
 
-from ray.serve._private.common import TargetCapacityDirection
+from ray.serve._private.common import DeploymentID, TargetCapacityDirection
 from ray.serve._private.controller import (
+    _get_autoscaling_metrics_delay_tag_keys,
+    _get_autoscaling_metrics_delay_tags,
     applications_match,
     calculate_target_capacity_direction,
 )
@@ -20,6 +22,58 @@
 )
 
 
+def test_autoscaling_metrics_delay_tags_include_high_cardinality_by_default(
+    monkeypatch,
+):
+    from ray.serve._private import controller
+
+    monkeypatch.setattr(
+        controller,
+        "RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS",
+        True,
+    )
+
+    assert _get_autoscaling_metrics_delay_tag_keys(("handle",)) == (
+        "deployment",
+        "application",
+        "handle",
+    )
+    assert _get_autoscaling_metrics_delay_tags(
+        DeploymentID(name="deployment", app_name="application"),
+        "handle",
+        "handle-id",
+    ) == {
+        "deployment": "deployment",
+        "application": "application",
+        "handle": "handle-id",
+    }
+
+
+def test_autoscaling_metrics_delay_tags_exclude_high_cardinality(
+    monkeypatch,
+):
+    from ray.serve._private import controller
+
+    monkeypatch.setattr(
+        controller,
+        "RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS",
+        False,
+    )
+
+    assert _get_autoscaling_metrics_delay_tag_keys(("replica",)) == (
+        "deployment",
+        "application",
+    )
+    assert _get_autoscaling_metrics_delay_tags(
+        DeploymentID(name="deployment", app_name="application"),
+        "replica",
+        "replica-id",
+    ) == {
+        "deployment": "deployment",
+        "application": "application",
+    }
+
+
 def create_app_config(name: str) -> ServeApplicationSchema:
     return ServeApplicationSchema(
         name=name, import_path=f"fake.{name}", route_prefix=f"/{name}"
diff --git a/python/ray/serve/tests/unit/test_deployment_state.py b/python/ray/serve/tests/unit/test_deployment_state.py
index 94c84c93505a..11f5d4c12e46 100644
--- a/python/ray/serve/tests/unit/test_deployment_state.py
+++ b/python/ray/serve/tests/unit/test_deployment_state.py
@@ -7,6 +7,10 @@
 
 from ray._common.ray_constants import DEFAULT_MAX_CONCURRENCY_ASYNC
 from ray._raylet import NodeID
+from ray.serve._private import (
+    deployment_state as deployment_state_module,
+    replica as replica_module,
+)
 from ray.serve._private.autoscaling_state import AutoscalingStateManager
 from ray.serve._private.common import (
     RUNNING_REQUESTS_KEY,
@@ -51,9 +55,15 @@
     DeploymentVersion,
     ReplicaStartupStatus,
     ReplicaStateContainer,
+    _get_replica_lifecycle_metric_tag_keys,
+    _get_replica_lifecycle_metric_tags,
 )
 from ray.serve._private.exceptions import DeploymentIsBeingDeletedError
 from ray.serve._private.long_poll import LongPollNamespace
+from ray.serve._private.replica import (
+    _get_replica_metric_default_tag_keys,
+    _get_replica_metric_default_tags,
+)
 from ray.serve._private.test_utils import (
     MockDeploymentActorWrapper,
     MockPlacementGroup,
@@ -73,6 +83,77 @@
 TEST_DEPLOYMENT_ID_2 = DeploymentID(name="test_deployment_2", app_name="test_app")
 
 
+def test_replica_lifecycle_metric_tags_include_high_cardinality_by_default(
+    monkeypatch,
+):
+    monkeypatch.setattr(
+        deployment_state_module,
+        "RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS",
+        True,
+    )
+
+    assert _get_replica_lifecycle_metric_tag_keys() == (
+        "deployment",
+        "replica",
+        "application",
+    )
+    assert _get_replica_lifecycle_metric_tags("replica-id") == {"replica": "replica-id"}
+
+
+def test_replica_lifecycle_metric_tags_exclude_high_cardinality(monkeypatch):
+    monkeypatch.setattr(
+        deployment_state_module,
+        "RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS",
+        False,
+    )
+
+    assert _get_replica_lifecycle_metric_tag_keys() == (
+        "deployment",
+        "application",
+    )
+    assert _get_replica_lifecycle_metric_tags("replica-id") is None
+
+
+def test_replica_metric_default_tags_include_high_cardinality_by_default(
+    monkeypatch,
+):
+    monkeypatch.setattr(
+        replica_module,
+        "RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS",
+        True,
+    )
+
+    assert _get_replica_metric_default_tag_keys(("exception_name",)) == (
+        "deployment",
+        "replica",
+        "application",
+        "exception_name",
+    )
+    assert _get_replica_metric_default_tags(TEST_DEPLOYMENT_ID, "replica-id") == {
+        "deployment": "test_deployment",
+        "application": "test_app",
+        "replica": "replica-id",
+    }
+
+
+def test_replica_metric_default_tags_exclude_high_cardinality(monkeypatch):
+    monkeypatch.setattr(
+        replica_module,
+        "RAY_SERVE_CONTROLLER_METRICS_INCLUDE_HIGH_CARDINALITY_TAGS",
+        False,
+    )
+
+    assert _get_replica_metric_default_tag_keys(("exception_name",)) == (
+        "deployment",
+        "application",
+        "exception_name",
+    )
+    assert _get_replica_metric_default_tags(TEST_DEPLOYMENT_ID, "replica-id") == {
+        "deployment": "test_deployment",
+        "application": "test_app",
+    }
+
+
 def deployment_info(
     version: Optional[str] = None,
     num_replicas: Optional[int] = 1,