diff --git a/packages/artifact/__tests__/artifactTwirpClient.test.ts b/packages/artifact/__tests__/artifactTwirpClient.test.ts
new file mode 100644
index 00000000..035031e1
--- /dev/null
+++ b/packages/artifact/__tests__/artifactTwirpClient.test.ts
@@ -0,0 +1,84 @@
+import {ArtifactHttpClient} from '../src/internal/shared/artifact-twirp-client'
+import {setSecret, debug} from '@actions/core'
+import {
+  CreateArtifactResponse,
+  GetSignedArtifactURLResponse
+} from '../src/generated/results/api/v1/artifact'
+
+jest.mock('@actions/core', () => ({
+  setSecret: jest.fn(),
+  info: jest.fn(),
+  debug: jest.fn()
+}))
+
+describe('ArtifactHttpClient', () => {
+  let client: ArtifactHttpClient
+
+  beforeEach(() => {
+    jest.clearAllMocks()
+    process.env['ACTIONS_RUNTIME_TOKEN'] = 'test-token'
+    process.env['ACTIONS_RESULTS_URL'] = 'https://example.com'
+    client = new ArtifactHttpClient('test-agent')
+  })
+
+  afterEach(() => {
+    delete process.env['ACTIONS_RUNTIME_TOKEN']
+    delete process.env['ACTIONS_RESULTS_URL']
+  })
+
+  describe('maskSecretUrls', () => {
+    it('should mask signed_upload_url', () => {
+      const response: CreateArtifactResponse = {
+        ok: true,
+        signedUploadUrl: 'https://example.com/upload?se=2025-03-05T16%3A47%3A23Z&sig=secret-token'
+      }
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).toHaveBeenCalledWith('secret-token')
+      expect(debug).toHaveBeenCalledWith('Masked signed_upload_url: https://example.com/upload?se=2025-03-05T16%3A47%3A23Z&sig=***')
+    })
+
+    it('should mask signed_download_url', () => {
+      const response: GetSignedArtifactURLResponse = {
+        signedUrl: 'https://example.com/download?se=2025-03-05T16%3A47%3A23Z&sig=secret-token'
+      }
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).toHaveBeenCalledWith('secret-token')
+      expect(debug).toHaveBeenCalledWith('Masked signed_download_url: https://example.com/download?se=2025-03-05T16%3A47%3A23Z&sig=***')
+    })
+
+    it('should not call setSecret if URLs are missing', () => {
+      const response = {} as CreateArtifactResponse
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).not.toHaveBeenCalled()
+    })
+
+    it('should mask only the sensitive token part of signed_upload_url', () => {
+      const response: CreateArtifactResponse = {
+        ok: true,
+        signedUploadUrl: 'https://example.com/upload?se=2025-03-05T16%3A47%3A23Z&sig=secret-token'
+      }
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).toHaveBeenCalledWith('secret-token')
+      expect(debug).toHaveBeenCalledWith('Masked signed_upload_url: https://example.com/upload?se=2025-03-05T16%3A47%3A23Z&sig=***')
+    })
+
+    it('should mask only the sensitive token part of signed_download_url', () => {
+      const response: GetSignedArtifactURLResponse = {
+        signedUrl: 'https://example.com/download?se=2025-03-05T16%3A47%3A23Z&sig=secret-token'
+      }
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).toHaveBeenCalledWith('secret-token')
+      expect(debug).toHaveBeenCalledWith('Masked signed_download_url: https://example.com/download?se=2025-03-05T16%3A47%3A23Z&sig=***')
+    })
+  })
+})
diff --git a/packages/artifact/src/internal/shared/artifact-twirp-client.ts b/packages/artifact/src/internal/shared/artifact-twirp-client.ts
index 00c65bc7..1d3e8c69 100644
--- a/packages/artifact/src/internal/shared/artifact-twirp-client.ts
+++ b/packages/artifact/src/internal/shared/artifact-twirp-client.ts
@@ -1,10 +1,14 @@
 import {HttpClient, HttpClientResponse, HttpCodes} from '@actions/http-client'
 import {BearerCredentialHandler} from '@actions/http-client/lib/auth'
-import {info, debug} from '@actions/core'
+import {setSecret, info, debug, maskSigUrl} from '@actions/core'
 import {ArtifactServiceClientJSON} from '../../generated'
 import {getResultsServiceUrl, getRuntimeToken} from './config'
 import {getUserAgentString} from './user-agent'
 import {NetworkError, UsageError} from './errors'
+import {
+  CreateArtifactResponse,
+  GetSignedArtifactURLResponse
+} from '../../generated/results/api/v1/artifact'
 
 // The twirp http client must implement this interface
 interface Rpc {
@@ -16,7 +20,7 @@ interface Rpc {
   ): Promise<object | Uint8Array>
 }
 
-class ArtifactHttpClient implements Rpc {
+export class ArtifactHttpClient implements Rpc {
   private httpClient: HttpClient
   private baseUrl: string
   private maxAttempts = 5
@@ -70,6 +74,17 @@ class ArtifactHttpClient implements Rpc {
     }
   }
 
+  maskSecretUrls(
+    body: CreateArtifactResponse | GetSignedArtifactURLResponse
+  ): void {
+    if ('signedUploadUrl' in body && body.signedUploadUrl) {
+      maskSigUrl(body.signedUploadUrl, 'signed_upload_url')
+    }
+    if ('signedUrl' in body && body.signedUrl) {
+      maskSigUrl(body.signedUrl, 'signed_url')
+    }
+  }
+
   async retryableRequest(
     operation: () => Promise<HttpClientResponse>
   ): Promise<{response: HttpClientResponse; body: object}> {
@@ -86,6 +101,7 @@ class ArtifactHttpClient implements Rpc {
         debug(`[Response] - ${response.message.statusCode}`)
         debug(`Headers: ${JSON.stringify(response.message.headers, null, 2)}`)
         const body = JSON.parse(rawBody)
+        this.maskSecretUrls(body)
         debug(`Body: ${JSON.stringify(body, null, 2)}`)
         if (this.isSuccessStatusCode(statusCode)) {
           return {response, body}
diff --git a/packages/cache/__tests__/cacheTwirpClient.test.ts b/packages/cache/__tests__/cacheTwirpClient.test.ts
new file mode 100644
index 00000000..dd38e8fe
--- /dev/null
+++ b/packages/cache/__tests__/cacheTwirpClient.test.ts
@@ -0,0 +1,98 @@
+import {
+  CreateCacheEntryResponse,
+  GetCacheEntryDownloadURLResponse
+} from '../src/generated/results/api/v1/cache'
+import {CacheServiceClient} from '../src/internal/shared/cacheTwirpClient'
+import {setSecret, debug} from '@actions/core'
+
+jest.mock('@actions/core', () => ({
+  setSecret: jest.fn(),
+  info: jest.fn(),
+  debug: jest.fn()
+}))
+
+describe('CacheServiceClient', () => {
+  let client: CacheServiceClient
+
+  beforeEach(() => {
+    jest.clearAllMocks()
+    process.env['ACTIONS_RUNTIME_TOKEN'] = 'test-token' // <-- set the required env variable
+    client = new CacheServiceClient('test-agent')
+  })
+
+  afterEach(() => {
+    delete process.env['ACTIONS_RUNTIME_TOKEN'] // <-- clean up after tests
+  })
+
+  describe('maskSecretUrls', () => {
+    it('should mask signedUploadUrl', () => {
+      const response = {
+        ok: true,
+        signedUploadUrl:
+          'https://example.com/upload?se=2025-03-05T16%3A47%3A23Z&sig=secret-token'
+      } as CreateCacheEntryResponse
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).toHaveBeenCalledWith('secret-token')
+      expect(debug).toHaveBeenCalledWith(
+        'Masked signedUploadUrl: https://example.com/upload?se=2025-03-05T16%3A47%3A23Z&sig=***'
+      )
+    })
+
+    it('should mask signedDownloadUrl', () => {
+      const response = {
+        ok: true,
+        signedDownloadUrl:
+          'https://example.com/download?se=2025-03-05T16%3A47%3A23Z&sig=secret-token',
+        matchedKey: 'cache-key'
+      } as GetCacheEntryDownloadURLResponse
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).toHaveBeenCalledWith('secret-token')
+      expect(debug).toHaveBeenCalledWith(
+        'Masked signedDownloadUrl: https://example.com/download?se=2025-03-05T16%3A47%3A23Z&sig=***'
+      )
+    })
+
+    it('should not call setSecret if URLs are missing', () => {
+      const response = {ok: true} as CreateCacheEntryResponse
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).not.toHaveBeenCalled()
+    })
+
+    it('should mask only the sensitive token part of signedUploadUrl', () => {
+      const response = {
+        ok: true,
+        signedUploadUrl:
+          'https://example.com/upload?se=2025-03-05T16%3A47%3A23Z&sig=secret-token'
+      } as CreateCacheEntryResponse
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).toHaveBeenCalledWith('secret-token')
+      expect(debug).toHaveBeenCalledWith(
+        'Masked signedUploadUrl: https://example.com/upload?se=2025-03-05T16%3A47%3A23Z&sig=***'
+      )
+    })
+
+    it('should mask only the sensitive token part of signedDownloadUrl', () => {
+      const response = {
+        ok: true,
+        signedDownloadUrl:
+          'https://example.com/download?se=2025-03-05T16%3A47%3A23Z&sig=secret-token',
+        matchedKey: 'cache-key'
+      } as GetCacheEntryDownloadURLResponse
+
+      client.maskSecretUrls(response)
+
+      expect(setSecret).toHaveBeenCalledWith('secret-token')
+      expect(debug).toHaveBeenCalledWith(
+        'Masked signedDownloadUrl: https://example.com/download?se=2025-03-05T16%3A47%3A23Z&sig=***'
+      )
+    })
+  })
+})
diff --git a/packages/cache/__tests__/saveCacheV2.test.ts b/packages/cache/__tests__/saveCacheV2.test.ts
index e96c2ac9..fed2c2a4 100644
--- a/packages/cache/__tests__/saveCacheV2.test.ts
+++ b/packages/cache/__tests__/saveCacheV2.test.ts
@@ -8,10 +8,16 @@ import * as tar from '../src/internal/tar'
 import {CacheServiceClientJSON} from '../src/generated/results/api/v1/cache.twirp-client'
 import * as cacheHttpClient from '../src/internal/cacheHttpClient'
 import {UploadOptions} from '../src/options'
+import {
+  CreateCacheEntryResponse,
+  GetCacheEntryDownloadURLResponse
+} from '../src/generated/results/api/v1/cache'
+import {CacheServiceClient} from '../src/internal/shared/cacheTwirpClient'
 
 let logDebugMock: jest.SpyInstance
 
 jest.mock('../src/internal/tar')
+jest.mock('@actions/core')
 
 const uploadFileMock = jest.fn()
 const blockBlobClientMock = jest.fn().mockImplementation(() => ({
diff --git a/packages/cache/src/internal/shared/cacheTwirpClient.ts b/packages/cache/src/internal/shared/cacheTwirpClient.ts
index 69d9a8fc..9c121121 100644
--- a/packages/cache/src/internal/shared/cacheTwirpClient.ts
+++ b/packages/cache/src/internal/shared/cacheTwirpClient.ts
@@ -1,4 +1,4 @@
-import {info, debug} from '@actions/core'
+import {info, debug, maskSigUrl} from '@actions/core'
 import {getUserAgentString} from './user-agent'
 import {NetworkError, UsageError} from './errors'
 import {getCacheServiceURL} from '../config'
@@ -6,6 +6,10 @@ import {getRuntimeToken} from '../cacheUtils'
 import {BearerCredentialHandler} from '@actions/http-client/lib/auth'
 import {HttpClient, HttpClientResponse, HttpCodes} from '@actions/http-client'
 import {CacheServiceClientJSON} from '../../generated/results/api/v1/cache.twirp-client'
+import {
+  CreateCacheEntryResponse,
+  GetCacheEntryDownloadURLResponse
+} from '../../generated/results/api/v1/cache'
 
 // The twirp http client must implement this interface
 interface Rpc {
@@ -24,7 +28,7 @@ interface Rpc {
  *
  * This class is used to interact with cache service v2.
  */
-class CacheServiceClient implements Rpc {
+export class CacheServiceClient implements Rpc {
   private httpClient: HttpClient
   private baseUrl: string
   private maxAttempts = 5
@@ -94,6 +98,7 @@ class CacheServiceClient implements Rpc {
         debug(`[Response] - ${response.message.statusCode}`)
         debug(`Headers: ${JSON.stringify(response.message.headers, null, 2)}`)
         const body = JSON.parse(rawBody)
+        this.maskSecretUrls(body)
         debug(`Body: ${JSON.stringify(body, null, 2)}`)
         if (this.isSuccessStatusCode(statusCode)) {
           return {response, body}
@@ -148,6 +153,17 @@ class CacheServiceClient implements Rpc {
     throw new Error(`Request failed`)
   }
 
+  maskSecretUrls(
+    body: CreateCacheEntryResponse | GetCacheEntryDownloadURLResponse
+  ): void {
+    if ('signedUploadUrl' in body && body.signedUploadUrl) {
+      maskSigUrl(body.signedUploadUrl, 'signedUploadUrl')
+    }
+    if ('signedDownloadUrl' in body && body.signedDownloadUrl) {
+      maskSigUrl(body.signedDownloadUrl, 'signedDownloadUrl')
+    }
+  }
+
   isSuccessStatusCode(statusCode?: number): boolean {
     if (!statusCode) return false
     return statusCode >= 200 && statusCode < 300
diff --git a/packages/core/src/core.ts b/packages/core/src/core.ts
index 0a141693..12359d0a 100644
--- a/packages/core/src/core.ts
+++ b/packages/core/src/core.ts
@@ -391,3 +391,19 @@ export {toPosixPath, toWin32Path, toPlatformPath} from './path-utils'
  * Platform utilities exports
  */
 export * as platform from './platform'
+
+/**
+ * Masks the `sig` parameter in a URL and sets it as a secret.
+ * @param url The URL containing the `sig` parameter.
+ * @param urlType The type of the URL (e.g., 'signed_upload_url', 'signed_download_url').
+ * @returns The URL with the `sig` parameter masked.
+ */
+export function maskSigUrl(url: string, urlType: string): string {
+  const sigMatch = url.match(/[?&]sig=([^&]+)/)
+  if (sigMatch) {
+    setSecret(sigMatch[1])
+    debug(`Masked ${urlType}: ${url.replace(sigMatch[1], '***')}`)
+    return url.replace(sigMatch[1], '***')
+  }
+  return url
+}