diff --git a/.github/workflows/storage.yml b/.github/workflows/storage.yml
index 6d9b6b7a543..877b90a4588 100644
--- a/.github/workflows/storage.yml
+++ b/.github/workflows/storage.yml
@@ -89,11 +89,8 @@ jobs:
     strategy:
       matrix:
         include:
-          - os: macos-13
-            xcode: Xcode_15.2
-            target: iOS
           - os: macos-14
-            xcode: Xcode_15.4
+            xcode: Xcode_16.2
             target: iOS
           - os: macos-15
             xcode: Xcode_16.2
@@ -132,6 +129,28 @@ jobs:
     - name: Unit Tests
       run: scripts/third_party/travis/retry.sh ./scripts/build.sh FirebaseStorageUnit ${{ matrix.target }} spm
 
+  catalyst:
+    # Don't run on private repo unless it is a PR.
+    if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
+    runs-on: macos-15
+    steps:
+    - uses: actions/checkout@v4
+    - uses: mikehardy/buildcache-action@c87cea0ccd718971d6cc39e672c4f26815b6c126
+      with:
+        cache_key: catalyst${{ matrix.os }}
+    - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
+    - name: Setup Bundler
+      run: scripts/setup_bundler.sh
+    - name: Xcode
+      run: sudo xcode-select -s /Applications/Xcode_16.2.app/Contents/Developer
+    - uses: nick-fields/retry@ce71cc2ab81d554ebbe88c79ab5975992d79ba08 # v3
+      with:
+        timeout_minutes: 120
+        max_attempts: 3
+        retry_on: error
+        retry_wait_seconds: 120
+        command: scripts/test_catalyst.sh FirebaseStorage test FirebaseStorage-Unit-unit
+
   quickstart:
     # Don't run on private repo unless it is a PR.
     if: (github.repository == 'Firebase/firebase-ios-sdk' && github.event_name == 'schedule') || github.event_name == 'pull_request'
@@ -169,7 +188,7 @@ jobs:
       plist_secret: ${{ secrets.GHASecretsGPGPassphrase1 }}
       signin_secret: ${{ secrets.GHASecretsGPGPassphrase1 }}
       LEGACY: true
-    runs-on: macos-14
+    runs-on: macos-15
     steps:
     - uses: actions/checkout@v4
     - uses: ruby/setup-ruby@354a1ad156761f5ee2b7b13fa8e09943a5e8d252 # v1
@@ -199,8 +218,8 @@ jobs:
       matrix:
         target: [ios, tvos, macos, watchos]
         build-env:
-          - os: macos-14
-            xcode: Xcode_15.3
+          - os: macos-15
+            xcode: Xcode_16.2
             tests: --skip-tests
           - os: macos-15
             xcode: Xcode_16.2
@@ -228,7 +247,7 @@ jobs:
         target: [ios, tvos, macos, watchos]
         build-env:
           - os: macos-14
-            xcode: Xcode_15.3
+            xcode: Xcode_16.2
           - os: macos-15
             xcode: Xcode_16.2
     runs-on: ${{ matrix.build-env.os }}
diff --git a/FirebaseStorage/Sources/Internal/StorageTokenAuthorizer.swift b/FirebaseStorage/Sources/Internal/StorageTokenAuthorizer.swift
index fbaa15a5fda..3dec3a3872a 100644
--- a/FirebaseStorage/Sources/Internal/StorageTokenAuthorizer.swift
+++ b/FirebaseStorage/Sources/Internal/StorageTokenAuthorizer.swift
@@ -17,7 +17,7 @@ import Foundation
 import FirebaseAppCheckInterop
 import FirebaseAuthInterop
 import FirebaseCore
-@_implementationOnly import FirebaseCoreExtension
+internal import FirebaseCoreExtension
 
 #if COCOAPODS
   import GTMSessionFetcher
diff --git a/FirebaseStorage/Sources/Storage.swift b/FirebaseStorage/Sources/Storage.swift
index b58cc4a8c30..b4eefff1ff1 100644
--- a/FirebaseStorage/Sources/Storage.swift
+++ b/FirebaseStorage/Sources/Storage.swift
@@ -19,7 +19,7 @@ import FirebaseAuthInterop
 import FirebaseCore
 
 // Avoids exposing internal FirebaseCore APIs to Swift users.
-@_implementationOnly import FirebaseCoreExtension
+internal import FirebaseCoreExtension
 
 /// Firebase Storage is a service that supports uploading and downloading binary objects,
 /// such as images, videos, and other files to Google Cloud Storage. Instances of `Storage`
diff --git a/FirebaseStorage/Sources/StorageUploadTask.swift b/FirebaseStorage/Sources/StorageUploadTask.swift
index c1ed2ccfd79..73cb1d5cb21 100644
--- a/FirebaseStorage/Sources/StorageUploadTask.swift
+++ b/FirebaseStorage/Sources/StorageUploadTask.swift
@@ -15,9 +15,9 @@
 import Foundation
 
 #if COCOAPODS
-  @_implementationOnly import GoogleUtilities
+  internal import GoogleUtilities
 #else
-  @_implementationOnly import GoogleUtilities_Environment
+  internal import GoogleUtilities_Environment
 #endif // COCOAPODS
 
 #if COCOAPODS
diff --git a/scripts/build.sh b/scripts/build.sh
index d5776e4e3c1..bb4c4ee8165 100755
--- a/scripts/build.sh
+++ b/scripts/build.sh
@@ -151,6 +151,7 @@ function CheckUnexpectedFailures() {
   fi
 }
 
+# TODO(ncooke3): Xcode 16 – remove -lt 15 after migration
 if [[ "$xcode_major" -lt 15 ]]; then
   ios_flags=(
     -sdk 'iphonesimulator'
@@ -572,10 +573,12 @@ case "$product-$platform-$method" in
 
     if check_secrets; then
       # Integration tests are only run on iOS to minimize flake failures.
+      # TODO(ncooke3): Add back "${ios_flags[@]}". See #14657.
       RunXcodebuild \
         -workspace 'gen/FirebaseStorage/FirebaseStorage.xcworkspace' \
         -scheme "FirebaseStorage-Unit-integration" \
-        "${ios_flags[@]}" \
+        -sdk 'iphonesimulator' \
+        -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.3.1' \
         "${xcb_flags[@]}" \
         test
     fi
@@ -591,10 +594,12 @@ case "$product-$platform-$method" in
 
     if check_secrets; then
       # Integration tests are only run on iOS to minimize flake failures.
+      # TODO(ncooke3): Add back "${ios_flags[@]}". See #14657.
       RunXcodebuild \
         -workspace 'gen/FirebaseStorage/FirebaseStorage.xcworkspace' \
         -scheme "FirebaseStorage-Unit-ObjCIntegration" \
-        "${ios_flags[@]}" \
+        -sdk 'iphonesimulator' \
+        -destination 'platform=iOS Simulator,name=iPhone 16,OS=18.3.1' \
         "${xcb_flags[@]}" \
         test
       fi