diff --git a/__tests__/setup-go.test.ts b/__tests__/setup-go.test.ts
index 78cabbf..a5eb16b 100644
--- a/__tests__/setup-go.test.ts
+++ b/__tests__/setup-go.test.ts
@@ -1421,7 +1421,8 @@ use .
       // Mock the installed Go binary reporting a different patch version
       execFileSpy.mockImplementation(() => 'go version go1.20.14 linux/amd64');
 
-      const toolPath = path.normalize('/cache/go-custom/1.20.14/x64');
+      const expectedToolName = im.customToolCacheName(customBaseUrl);
+      const toolPath = path.normalize(`/cache/${expectedToolName}/1.20.14/x64`);
       cacheSpy.mockImplementation(async () => toolPath);
 
       await main.run();
@@ -1432,7 +1433,7 @@ use .
       // Cache key should use actual version, not the input spec
       expect(cacheSpy).toHaveBeenCalledWith(
         expect.any(String),
-        'go-custom',
+        expectedToolName,
         '1.20.14',
         'x64'
       );
@@ -1558,7 +1559,8 @@ use .
       findSpy.mockImplementation(() => '');
       dlSpy.mockImplementation(async () => '/some/temp/path');
       extractTarSpy.mockImplementation(async () => '/some/other/temp/path');
-      const toolPath = path.normalize('/cache/go-custom/1.25.0/x64');
+      const expectedToolName = im.customToolCacheName(customBaseUrl);
+      const toolPath = path.normalize(`/cache/${expectedToolName}/1.25.0/x64`);
       cacheSpy.mockImplementation(async () => toolPath);
 
       await main.run();
diff --git a/dist/setup/index.js b/dist/setup/index.js
index 386ed78..eacc56b 100644
--- a/dist/setup/index.js
+++ b/dist/setup/index.js
@@ -77034,6 +77034,7 @@ var __importDefault = (this && this.__importDefault) || function (mod) {
 Object.defineProperty(exports, "__esModule", ({ value: true }));
 exports.GOTOOLCHAIN_LOCAL_VAL = exports.GOTOOLCHAIN_ENV_VAR = void 0;
 exports.getGo = getGo;
+exports.customToolCacheName = customToolCacheName;
 exports.extractGoArchive = extractGoArchive;
 exports.getManifest = getManifest;
 exports.getInfoFromManifest = getInfoFromManifest;
@@ -77049,6 +77050,7 @@ const path = __importStar(__nccwpck_require__(16928));
 const semver = __importStar(__nccwpck_require__(62088));
 const httpm = __importStar(__nccwpck_require__(54844));
 const sys = __importStar(__nccwpck_require__(57666));
+const crypto_1 = __importDefault(__nccwpck_require__(76982));
 const child_process_1 = __importDefault(__nccwpck_require__(35317));
 const fs_1 = __importDefault(__nccwpck_require__(79896));
 const os_1 = __importDefault(__nccwpck_require__(70857));
@@ -77101,7 +77103,9 @@ function getGo(versionSpec_1, checkLatest_1, auth_1) {
         }
         // Use a distinct tool cache name for custom downloads to avoid
         // colliding with the runner's pre-installed Go
-        const toolCacheName = customBaseUrl ? 'go-custom' : 'go';
+        const toolCacheName = customBaseUrl
+            ? customToolCacheName(customBaseUrl)
+            : 'go';
         // check cache
         const toolPath = tc.find(toolCacheName, versionSpec, arch);
         // If not found in cache, download
@@ -77237,6 +77241,10 @@ function addExecutablesToToolCache(extPath_1, info_1, arch_1) {
             (yield tc.cacheDir(extPath, toolName, version, arch)));
     });
 }
+function customToolCacheName(baseUrl) {
+    const hash = crypto_1.default.createHash('sha256').update(baseUrl).digest('hex');
+    return `go-${hash.substring(0, 8)}`;
+}
 function installGoVersion(info_1, auth_1, arch_1) {
     return __awaiter(this, arguments, void 0, function* (info, auth, arch, toolName = 'go') {
         core.info(`Acquiring ${info.resolvedVersion} from ${info.downloadUrl}`);
diff --git a/src/installer.ts b/src/installer.ts
index 7a08c5d..a4938c8 100644
--- a/src/installer.ts
+++ b/src/installer.ts
@@ -4,6 +4,7 @@ import * as path from 'path';
 import * as semver from 'semver';
 import * as httpm from '@actions/http-client';
 import * as sys from './system';
+import crypto from 'crypto';
 import cp from 'child_process';
 import fs from 'fs';
 import os from 'os';
@@ -112,7 +113,9 @@ export async function getGo(
 
   // Use a distinct tool cache name for custom downloads to avoid
   // colliding with the runner's pre-installed Go
-  const toolCacheName = customBaseUrl ? 'go-custom' : 'go';
+  const toolCacheName = customBaseUrl
+    ? customToolCacheName(customBaseUrl)
+    : 'go';
 
   // check cache
   const toolPath = tc.find(toolCacheName, versionSpec, arch);
@@ -294,6 +297,11 @@ async function addExecutablesToToolCache(
   );
 }
 
+export function customToolCacheName(baseUrl: string): string {
+  const hash = crypto.createHash('sha256').update(baseUrl).digest('hex');
+  return `go-${hash.substring(0, 8)}`;
+}
+
 async function installGoVersion(
   info: IGoVersionInfo,
   auth: string | undefined,