diff --git a/cloud_sql/mysql_instance_custom_subject_alternative_names/main.tf b/cloud_sql/mysql_instance_custom_subject_alternative_names/main.tf
new file mode 100644
index 00000000..7cbd7da0
--- /dev/null
+++ b/cloud_sql/mysql_instance_custom_subject_alternative_names/main.tf
@@ -0,0 +1,108 @@
+/**
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+# [START cloud_sql_mysql_instance_service_identity]
+resource "google_project_service_identity" "default" {
+  provider = google-beta
+  service  = "sqladmin.googleapis.com"
+}
+# [END cloud_sql_mysql_instance_service_identity]
+
+# [START cloud_sql_mysql_privateca_ca_pool_suffix]
+resource "random_string" "default" {
+  length  = 10
+  special = false
+  upper   = false
+}
+# [END cloud_sql_mysql_privateca_ca_pool_suffix]
+
+# [START cloud_sql_mysql_instance_ca_pool]
+resource "google_privateca_ca_pool" "default" {
+  name     = "customer-ca-pool-${random_string.default.result}"
+  location = "asia-northeast1"
+  tier     = "DEVOPS"
+  publishing_options {
+    publish_ca_cert = false
+    publish_crl     = false
+  }
+}
+# [END cloud_sql_mysql_instance_ca_pool]
+
+# [START cloud_sql_mysql_instance_ca]
+# This is required for setting up customer managed CAS (Certificate Authority Service) instances.
+resource "google_privateca_certificate_authority" "default" {
+  pool                                   = google_privateca_ca_pool.default.name
+  certificate_authority_id               = "my-certificate-authority"
+  location                               = "asia-northeast1"
+  lifetime                               = "86400s"
+  type                                   = "SELF_SIGNED"
+  deletion_protection                    = false # set to "true" in production
+  skip_grace_period                      = true
+  ignore_active_certificates_on_deletion = true
+  config {
+    subject_config {
+      subject {
+        organization = "my organization"
+        common_name  = "my certificate authority name"
+      }
+    }
+    x509_config {
+      ca_options {
+        is_ca = true
+      }
+      key_usage {
+        base_key_usage {
+          cert_sign = true
+          crl_sign  = true
+        }
+        extended_key_usage {
+          server_auth = false
+        }
+      }
+    }
+  }
+  key_spec {
+    algorithm = "RSA_PKCS1_4096_SHA256"
+  }
+}
+# [END cloud_sql_mysql_instance_ca]
+
+# [START cloud_sql_mysql_instance_iam_granting]
+resource "google_privateca_ca_pool_iam_member" "default" {
+  ca_pool = google_privateca_ca_pool.default.id
+  role    = "roles/privateca.certificateRequester"
+
+  member = "serviceAccount:${google_project_service_identity.default.email}"
+}
+# [END cloud_sql_mysql_instance_iam_granting]
+
+# [START cloud_sql_mysql_instance_custom_subject_alternative_names]
+resource "google_sql_database_instance" "default" {
+  name             = "mysql-instance"
+  region           = "asia-northeast1"
+  database_version = "MYSQL_8_4"
+  settings {
+    edition = "ENTERPRISE"
+    tier    = "db-f1-micro"
+    ip_configuration {
+      # The following server CA mode lets the instance use customer-managed CAS CA to issue server certificates.
+      # https://cloud.google.com/sql/docs/mysql/admin-api/rest/v1beta4/instances#ipconfiguration
+      server_ca_mode                   = "CUSTOMER_MANAGED_CAS_CA"
+      server_ca_pool                   = google_privateca_ca_pool.default.id
+      custom_subject_alternative_names = ["customSan.test.com"]
+    }
+  }
+}
+# [END cloud_sql_mysql_instance_custom_subject_alternative_names]
diff --git a/cloud_sql/postgres_instance_custom_subject_alternative_names/main.tf b/cloud_sql/postgres_instance_custom_subject_alternative_names/main.tf
new file mode 100644
index 00000000..e61f150d
--- /dev/null
+++ b/cloud_sql/postgres_instance_custom_subject_alternative_names/main.tf
@@ -0,0 +1,108 @@
+/**
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+# [START cloud_sql_postgres_instance_service_identity]
+resource "google_project_service_identity" "default" {
+  provider = google-beta
+  service  = "sqladmin.googleapis.com"
+}
+# [END cloud_sql_postgres_instance_service_identity]
+
+# [START cloud_sql_postgres_privateca_ca_pool_suffix]
+resource "random_string" "default" {
+  length  = 10
+  special = false
+  upper   = false
+}
+# [END cloud_sql_postgres_privateca_ca_pool_suffix]
+
+# [START cloud_sql_postgres_instance_ca_pool]
+resource "google_privateca_ca_pool" "default" {
+  name     = "customer-ca-pool-${random_string.default.result}"
+  location = "asia-northeast1"
+  tier     = "DEVOPS"
+  publishing_options {
+    publish_ca_cert = false
+    publish_crl     = false
+  }
+}
+# [END cloud_sql_postgres_instance_ca_pool]
+
+# [START cloud_sql_postgres_instance_ca]
+# This is required for setting up customer managed CAS (Certificate Authority Service) instances.
+resource "google_privateca_certificate_authority" "default" {
+  pool                                   = google_privateca_ca_pool.default.name
+  certificate_authority_id               = "my-certificate-authority"
+  location                               = "asia-northeast1"
+  lifetime                               = "86400s"
+  type                                   = "SELF_SIGNED"
+  deletion_protection                    = false # set to "true" in production
+  skip_grace_period                      = true
+  ignore_active_certificates_on_deletion = true
+  config {
+    subject_config {
+      subject {
+        organization = "my organization"
+        common_name  = "my certificate authority name"
+      }
+    }
+    x509_config {
+      ca_options {
+        is_ca = true
+      }
+      key_usage {
+        base_key_usage {
+          cert_sign = true
+          crl_sign  = true
+        }
+        extended_key_usage {
+          server_auth = false
+        }
+      }
+    }
+  }
+  key_spec {
+    algorithm = "RSA_PKCS1_4096_SHA256"
+  }
+}
+# [END cloud_sql_postgres_instance_ca]
+
+# [START cloud_sql_postgres_instance_iam_granting]
+resource "google_privateca_ca_pool_iam_member" "default" {
+  ca_pool = google_privateca_ca_pool.default.id
+  role    = "roles/privateca.certificateRequester"
+
+  member = "serviceAccount:${google_project_service_identity.default.email}"
+}
+# [END cloud_sql_postgres_instance_iam_granting]
+
+# [START cloud_sql_postgres_instance_custom_subject_alternative_names]
+resource "google_sql_database_instance" "default" {
+  name             = "postgres-instance"
+  region           = "asia-northeast1"
+  database_version = "POSTGRES_17"
+  settings {
+    edition = "ENTERPRISE"
+    tier    = "db-f1-micro"
+    ip_configuration {
+      # The following server CA mode lets the instance use customer-managed CAS CA to issue server certificates.
+      # https://cloud.google.com/sql/docs/postgres/admin-api/rest/v1beta4/instances#ipconfiguration
+      server_ca_mode                   = "CUSTOMER_MANAGED_CAS_CA"
+      server_ca_pool                   = google_privateca_ca_pool.default.id
+      custom_subject_alternative_names = ["customSan.test.com"]
+    }
+  }
+}
+# [END cloud_sql_postgres_instance_custom_subject_alternative_names]
diff --git a/cloud_sql/sqlserver_instance_custom_subject_alternative_names/main.tf b/cloud_sql/sqlserver_instance_custom_subject_alternative_names/main.tf
new file mode 100644
index 00000000..354d7e4c
--- /dev/null
+++ b/cloud_sql/sqlserver_instance_custom_subject_alternative_names/main.tf
@@ -0,0 +1,108 @@
+/**
+ * Copyright 2025 Google LLC
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+# [START cloud_sql_sqlserver_instance_service_identity]
+resource "google_project_service_identity" "default" {
+  provider = google-beta
+  service  = "sqladmin.googleapis.com"
+}
+# [END cloud_sql_sqlserver_instance_service_identity]
+
+# [START cloud_sql_sqlserver_privateca_ca_pool_suffix]
+resource "random_string" "default" {
+  length  = 10
+  special = false
+  upper   = false
+}
+# [END cloud_sql_sqlserver_privateca_ca_pool_suffix]
+
+# [START cloud_sql_sqlserver_instance_ca_pool]
+resource "google_privateca_ca_pool" "default" {
+  name     = "customer-ca-pool-${random_string.default.result}"
+  location = "asia-northeast1"
+  tier     = "DEVOPS"
+  publishing_options {
+    publish_ca_cert = false
+    publish_crl     = false
+  }
+}
+# [END cloud_sql_sqlserver_instance_ca_pool]
+
+# [START cloud_sql_sqlserver_instance_ca]
+# This is required for setting up customer managed CAS (Certificate Authority Service) instances.
+resource "google_privateca_certificate_authority" "default" {
+  pool                                   = google_privateca_ca_pool.default.name
+  certificate_authority_id               = "my-certificate-authority"
+  location                               = "asia-northeast1"
+  lifetime                               = "86400s"
+  type                                   = "SELF_SIGNED"
+  deletion_protection                    = false # set to "true" in production
+  skip_grace_period                      = true
+  ignore_active_certificates_on_deletion = true
+  config {
+    subject_config {
+      subject {
+        organization = "my organization"
+        common_name  = "my certificate authority name"
+      }
+    }
+    x509_config {
+      ca_options {
+        is_ca = true
+      }
+      key_usage {
+        base_key_usage {
+          cert_sign = true
+          crl_sign  = true
+        }
+        extended_key_usage {
+          server_auth = false
+        }
+      }
+    }
+  }
+  key_spec {
+    algorithm = "RSA_PKCS1_4096_SHA256"
+  }
+}
+# [END cloud_sql_sqlserver_instance_ca]
+
+# [START cloud_sql_sqlserver_instance_iam_granting]
+resource "google_privateca_ca_pool_iam_member" "default" {
+  ca_pool = google_privateca_ca_pool.default.id
+  role    = "roles/privateca.certificateRequester"
+
+  member = "serviceAccount:${google_project_service_identity.default.email}"
+}
+# [END cloud_sql_sqlserver_instance_iam_granting]
+
+# [START cloud_sql_sqlserver_instance_custom_subject_alternative_names]
+resource "google_sql_database_instance" "default" {
+  name             = "sqlserver-instance"
+  region           = "asia-northeast1"
+  database_version = "SQLSERVER_2022_STANDARD"
+  root_password    = "INSERT-PASSWORD-HERE"
+  settings {
+    tier = "db-custom-2-7680"
+    ip_configuration {
+      # The following server CA mode lets the instance use customer-managed CAS CA to issue server certificates.
+      # https://cloud.google.com/sql/docs/sqlserver/admin-api/rest/v1beta4/instances#ipconfiguration
+      server_ca_mode                   = "CUSTOMER_MANAGED_CAS_CA"
+      server_ca_pool                   = google_privateca_ca_pool.default.id
+      custom_subject_alternative_names = ["customSan.test.com"]
+    }
+  }
+}
+# [END cloud_sql_sqlserver_instance_custom_subject_alternative_names]