diff --git a/packages/core/src/core/loggingContentGenerator.ts b/packages/core/src/core/loggingContentGenerator.ts
index b8cf49a091..697cca5cac 100644
--- a/packages/core/src/core/loggingContentGenerator.ts
+++ b/packages/core/src/core/loggingContentGenerator.ts
@@ -33,6 +33,7 @@ import { CodeAssistServer } from '../code_assist/server.js';
 import { toContents } from '../code_assist/converter.js';
 import { isStructuredError } from '../utils/quotaErrorDetection.js';
 import { runInDevTraceSpan, type SpanMetadata } from '../telemetry/trace.js';
+import { resolveVertexServerDetails } from '../utils/baseUrlUtils.js';
 
 interface StructuredError {
   status: number;
@@ -94,6 +95,10 @@ export class LoggingContentGenerator implements ContentGenerator {
 
     // Case 2: Using an API key for Vertex AI.
     if (genConfig?.vertexai) {
+      const vertexCustomServerDetails = resolveVertexServerDetails();
+      if (vertexCustomServerDetails) {
+        return vertexCustomServerDetails;
+      }
       const location = process.env['GOOGLE_CLOUD_LOCATION'];
       if (location) {
         return { address: `${location}-aiplatform.googleapis.com`, port: 443 };
diff --git a/packages/core/src/utils/baseUrlUtils.ts b/packages/core/src/utils/baseUrlUtils.ts
new file mode 100644
index 0000000000..bfda52bf58
--- /dev/null
+++ b/packages/core/src/utils/baseUrlUtils.ts
@@ -0,0 +1,14 @@
+/**
+ * @license
+ * Copyright 2025 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import type { ServerDetails } from '../telemetry/types.js';
+
+export function resolveVertexServerDetails(): ServerDetails | undefined {
+  if (process.env['GEMINI_CLI_VERTEX_BASE_URL'] === undefined) {
+    return undefined;
+  }
+  return { address: process.env['GEMINI_CLI_VERTEX_BASE_URL'], port: 443 };
+}