diff --git a/x-pack/plugins/monitoring/public/lib/internal_monitoring_toasts.tsx b/x-pack/plugins/monitoring/public/lib/internal_monitoring_toasts.tsx
new file mode 100644
index 00000000000000..b6ecb631d005a7
--- /dev/null
+++ b/x-pack/plugins/monitoring/public/lib/internal_monitoring_toasts.tsx
@@ -0,0 +1,123 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import React from 'react';
+import { i18n } from '@kbn/i18n';
+import { FormattedMessage } from '@kbn/i18n/react';
+import { EuiSpacer, EuiLink } from '@elastic/eui';
+import { Legacy } from '../legacy_shims';
+import { toMountPoint } from '../../../../../src/plugins/kibana_react/public';
+import { isInSetupMode, toggleSetupMode } from './setup_mode';
+
+export interface MonitoringIndicesTypes {
+  legacyIndices: number;
+  metricbeatIndices: number;
+}
+
+const enterSetupModeLabel = () =>
+  i18n.translate('xpack.monitoring.internalMonitoringToast.enterSetupMode', {
+    defaultMessage: 'Enter setup mode',
+  });
+
+const learnMoreLabel = () =>
+  i18n.translate('xpack.monitoring.internalMonitoringToast.learnMoreAction', {
+    defaultMessage: 'Learn more',
+  });
+
+const showIfLegacyOnlyIndices = () => {
+  const { ELASTIC_WEBSITE_URL } = Legacy.shims.docLinks;
+  const toast = Legacy.shims.toastNotifications.addWarning({
+    title: toMountPoint(
+      <FormattedMessage
+        id="xpack.monitoring.internalMonitoringToast.title"
+        defaultMessage="Internal Monitoring Detected"
+      />
+    ),
+    text: toMountPoint(
+      <div>
+        <p>
+          {i18n.translate('xpack.monitoring.internalMonitoringToast.description', {
+            defaultMessage: `It appears you are using "Legacy Collection" for Stack Monitoring. 
+            This method of monitoring will no longer be supported in the next major release (8.0.0). 
+            Please follow the steps in setup mode to start monitoring with Metricbeat.`,
+          })}
+        </p>
+        <EuiLink
+          onClick={() => {
+            Legacy.shims.toastNotifications.remove(toast);
+            toggleSetupMode(true);
+          }}
+        >
+          {enterSetupModeLabel()}
+        </EuiLink>
+
+        <EuiSpacer />
+        <EuiLink
+          href={`${ELASTIC_WEBSITE_URL}blog/external-collection-for-elastic-stack-monitoring-is-now-available-via-metricbeat`}
+          external
+          target="_blank"
+        >
+          {learnMoreLabel()}
+        </EuiLink>
+      </div>
+    ),
+  });
+};
+
+const showIfLegacyAndMetricbeatIndices = () => {
+  const { ELASTIC_WEBSITE_URL } = Legacy.shims.docLinks;
+  const toast = Legacy.shims.toastNotifications.addWarning({
+    title: toMountPoint(
+      <FormattedMessage
+        id="xpack.monitoring.internalAndMetricbeatMonitoringToast.title"
+        defaultMessage="Partial Legacy Monitoring Detected"
+      />
+    ),
+    text: toMountPoint(
+      <div>
+        <p>
+          {i18n.translate('xpack.monitoring.internalAndMetricbeatMonitoringToast.description', {
+            defaultMessage: `It appears you are using both Metricbeat and "Legacy Collection" for Stack Monitoring. 
+            In 8.0.0, you must use Metricbeat to collect monitoring data. 
+            Please follow the steps in setup mode to migrate the rest of the monitoring to Metricbeat.`,
+          })}
+        </p>
+        <EuiLink
+          onClick={() => {
+            Legacy.shims.toastNotifications.remove(toast);
+            toggleSetupMode(true);
+          }}
+        >
+          {enterSetupModeLabel()}
+        </EuiLink>
+
+        <EuiSpacer />
+        <EuiLink
+          href={`${ELASTIC_WEBSITE_URL}blog/external-collection-for-elastic-stack-monitoring-is-now-available-via-metricbeat`}
+          external
+          target="_blank"
+        >
+          {learnMoreLabel()}
+        </EuiLink>
+      </div>
+    ),
+  });
+};
+
+export const showInternalMonitoringToast = ({
+  legacyIndices,
+  metricbeatIndices,
+}: MonitoringIndicesTypes) => {
+  if (isInSetupMode()) {
+    return;
+  }
+
+  if (legacyIndices && !metricbeatIndices) {
+    showIfLegacyOnlyIndices();
+  } else if (legacyIndices && metricbeatIndices) {
+    showIfLegacyAndMetricbeatIndices();
+  }
+};
diff --git a/x-pack/plugins/monitoring/public/services/clusters.js b/x-pack/plugins/monitoring/public/services/clusters.js
index 5173984dbe868a..7f772ac1e1bcdc 100644
--- a/x-pack/plugins/monitoring/public/services/clusters.js
+++ b/x-pack/plugins/monitoring/public/services/clusters.js
@@ -7,6 +7,7 @@
 import { ajaxErrorHandlersProvider } from '../lib/ajax_error_handler';
 import { Legacy } from '../legacy_shims';
 import { STANDALONE_CLUSTER_CLUSTER_UUID } from '../../common/constants';
+import { showInternalMonitoringToast } from '../lib/internal_monitoring_toasts';
 import { showSecurityToast } from '../alerts/lib/security_toasts';
 
 function formatClusters(clusters) {
@@ -21,6 +22,7 @@ function formatCluster(cluster) {
 }
 
 let once = false;
+let inTransit = false;
 
 export function monitoringClustersProvider($injector) {
   return (clusterUuid, ccs, codePaths) => {
@@ -63,19 +65,39 @@ export function monitoringClustersProvider($injector) {
       });
     }
 
-    if (!once) {
+    function ensureMetricbeatEnabled() {
+      if (Legacy.shims.isCloud) {
+        return Promise.resolve();
+      }
+
+      return $http
+        .get('../api/monitoring/v1/elasticsearch_settings/check/internal_monitoring')
+        .then(({ data }) => {
+          showInternalMonitoringToast({
+            legacyIndices: data.legacy_indices,
+            metricbeatIndices: data.mb_indices,
+          });
+        })
+        .catch((err) => {
+          const Private = $injector.get('Private');
+          const ajaxErrorHandlers = Private(ajaxErrorHandlersProvider);
+          return ajaxErrorHandlers(err);
+        });
+    }
+
+    if (!once && !inTransit) {
+      inTransit = true;
       return getClusters().then((clusters) => {
         if (clusters.length) {
-          return ensureAlertsEnabled()
-            .then(({ data }) => {
+          Promise.all([ensureAlertsEnabled(), ensureMetricbeatEnabled()])
+            .then(([{ data }]) => {
               showSecurityToast(data);
               once = true;
-              return clusters;
             })
             .catch(() => {
               // Intentionally swallow the error as this will retry the next page load
-              return clusters;
-            });
+            })
+            .finally(() => (inTransit = false));
         }
         return clusters;
       });
diff --git a/x-pack/plugins/monitoring/server/routes/api/v1/elasticsearch_settings/check/internal_monitoring.ts b/x-pack/plugins/monitoring/server/routes/api/v1/elasticsearch_settings/check/internal_monitoring.ts
new file mode 100644
index 00000000000000..4473d824c9e307
--- /dev/null
+++ b/x-pack/plugins/monitoring/server/routes/api/v1/elasticsearch_settings/check/internal_monitoring.ts
@@ -0,0 +1,85 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+import { RequestHandlerContext } from 'kibana/server';
+// @ts-ignore
+import { getIndexPatterns } from '../../../../../lib/cluster/get_index_patterns';
+// @ts-ignore
+import { handleError } from '../../../../../lib/errors';
+import { RouteDependencies } from '../../../../../types';
+
+const queryBody = {
+  size: 0,
+  aggs: {
+    types: {
+      terms: {
+        field: '_index',
+        size: 10,
+      },
+    },
+  },
+};
+
+const checkLatestMonitoringIsLegacy = async (context: RequestHandlerContext, index: string) => {
+  const { client: esClient } = context.core.elasticsearch.legacy;
+  const result = await esClient.callAsCurrentUser('search', {
+    index,
+    body: queryBody,
+  });
+
+  const { aggregations } = result;
+  const counts = {
+    legacyIndicesCount: 0,
+    mbIndicesCount: 0,
+  };
+
+  if (!aggregations) {
+    return counts;
+  }
+
+  const {
+    types: { buckets },
+  } = aggregations;
+  counts.mbIndicesCount = buckets.filter(({ key }: { key: string }) => key.includes('-mb-')).length;
+
+  counts.legacyIndicesCount = buckets.length - counts.mbIndicesCount;
+  return counts;
+};
+
+export function internalMonitoringCheckRoute(server: unknown, npRoute: RouteDependencies) {
+  npRoute.router.get(
+    {
+      path: '/api/monitoring/v1/elasticsearch_settings/check/internal_monitoring',
+      validate: false,
+    },
+    async (context, _request, response) => {
+      try {
+        const typeCount = {
+          legacy_indices: 0,
+          mb_indices: 0,
+        };
+
+        const { esIndexPattern, kbnIndexPattern, lsIndexPattern } = getIndexPatterns(server);
+        const indexCounts = await Promise.all([
+          checkLatestMonitoringIsLegacy(context, esIndexPattern),
+          checkLatestMonitoringIsLegacy(context, kbnIndexPattern),
+          checkLatestMonitoringIsLegacy(context, lsIndexPattern),
+        ]);
+
+        indexCounts.forEach((counts) => {
+          typeCount.legacy_indices += counts.legacyIndicesCount;
+          typeCount.mb_indices += counts.mbIndicesCount;
+        });
+
+        return response.ok({
+          body: typeCount,
+        });
+      } catch (err) {
+        throw handleError(err);
+      }
+    }
+  );
+}
diff --git a/x-pack/plugins/monitoring/server/routes/api/v1/elasticsearch_settings/index.js b/x-pack/plugins/monitoring/server/routes/api/v1/elasticsearch_settings/index.js
index d7ef71efc0b519..906057d2218686 100644
--- a/x-pack/plugins/monitoring/server/routes/api/v1/elasticsearch_settings/index.js
+++ b/x-pack/plugins/monitoring/server/routes/api/v1/elasticsearch_settings/index.js
@@ -4,6 +4,7 @@
  * you may not use this file except in compliance with the Elastic License.
  */
 
+export { internalMonitoringCheckRoute } from './check/internal_monitoring';
 export { clusterSettingsCheckRoute } from './check/cluster';
 export { nodesSettingsCheckRoute } from './check/nodes';
 export { setCollectionEnabledRoute } from './set/collection_enabled';
diff --git a/x-pack/plugins/monitoring/server/routes/api/v1/ui.js b/x-pack/plugins/monitoring/server/routes/api/v1/ui.js
index de0213ec84689d..e8daf525824377 100644
--- a/x-pack/plugins/monitoring/server/routes/api/v1/ui.js
+++ b/x-pack/plugins/monitoring/server/routes/api/v1/ui.js
@@ -20,6 +20,7 @@ export {
   ccrShardRoute,
 } from './elasticsearch';
 export {
+  internalMonitoringCheckRoute,
   clusterSettingsCheckRoute,
   nodesSettingsCheckRoute,
   setCollectionEnabledRoute,
diff --git a/x-pack/test/functional/apps/monitoring/time_filter.js b/x-pack/test/functional/apps/monitoring/time_filter.js
index d7ffdb4a7900db..11557d995218e8 100644
--- a/x-pack/test/functional/apps/monitoring/time_filter.js
+++ b/x-pack/test/functional/apps/monitoring/time_filter.js
@@ -7,6 +7,8 @@
 import expect from '@kbn/expect';
 import { getLifecycleMethods } from './_get_lifecycle_methods';
 
+const delay = (ms) => new Promise((resolve) => setTimeout(resolve, ms));
+
 export default function ({ getService, getPageObjects }) {
   const PageObjects = getPageObjects(['header', 'timePicker']);
   const testSubjects = getService('testSubjects');
@@ -35,6 +37,11 @@ export default function ({ getService, getPageObjects }) {
     });
 
     it('should send another request when changing the time picker', async () => {
+      /**
+       * TODO: The value should either be removed or lowered after:
+       * https://github.com/elastic/kibana/issues/72997 is resolved
+       */
+      await delay(3000);
       await PageObjects.timePicker.setAbsoluteRange(
         'Aug 15, 2016 @ 21:00:00.000',
         'Aug 16, 2016 @ 00:00:00.000'