diff --git a/scripts/check_secrets.sh b/scripts/check_secrets.sh
index 4db1540f00c..ea289feb4b4 100755
--- a/scripts/check_secrets.sh
+++ b/scripts/check_secrets.sh
@@ -17,7 +17,6 @@
 
 # Check if secrets are available for multiple CI's
 
-set -x
 echo "GITHUB_BASE_REF: ${GITHUB_BASE_REF:-}"
 echo "GITHUB_HEAD_REF: ${GITHUB_HEAD_REF:-}"
 
diff --git a/scripts/setup_quickstart_spm.sh b/scripts/setup_quickstart_spm.sh
new file mode 100755
index 00000000000..39165c085ce
--- /dev/null
+++ b/scripts/setup_quickstart_spm.sh
@@ -0,0 +1,257 @@
+#!/usr/bin/env bash
+
+# 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.
+
+# Script to run in a CI `before_install` phase to setup a SPM-based
+# quickstart repo so that it can be used for integration testing.
+
+set -euo pipefail
+
+# Define testing mode constants.
+readonly NIGHTLY_RELEASE_TESTING="nightly_release_testing"
+readonly PRERELEASE_TESTING="prerelease_testing"
+
+# All script logic is contained in functions. The main function is called at
+# the end.
+# Global variables:
+#   - readonly constants are defined at the top.
+#   - scripts_dir and root_dir are set after constants.
+
+scripts_dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+root_dir="$(dirname "$scripts_dir")"
+
+print_usage() {
+  cat <<EOF
+Usage: $(basename "$0") <sample_name> [testing_mode]
+
+This script sets up a quickstart sample for SPM integration testing.
+
+ARGUMENTS:
+  <sample_name>   The name of the quickstart sample directory
+                  (e.g., "authentication").
+  [testing_mode]  Optional. Specifies the testing mode. Can be one of:
+                  - "${NIGHTLY_RELEASE_TESTING}": Points SPM to the latest
+                    CocoaPods tag.
+                  - "${PRERELEASE_TESTING}": Points SPM to the tip of the main
+                    branch.
+                  - (default): Points SPM to the current commit for PR testing.
+
+ENVIRONMENT VARIABLES:
+  QUICKSTART_REPO: Optional. Path to a local clone of the quickstart-ios repo.
+                   If not set, the script will clone it from GitHub.
+                   Example:
+                   QUICKSTART_REPO=/path/to/quickstart-ios $(basename "$0") authentication
+
+  QUICKSTART_BRANCH: Optional. The branch to checkout in the quickstart repo.
+                     Defaults to the repo's default branch.
+                     Example:
+                     QUICKSTART_BRANCH=my-feature-branch $(basename "$0") authentication
+
+  BYPASS_SECRET_CHECK: Optional. Set to "true" to bypass the CI secret check
+                       for local runs.
+                       Example:
+                       BYPASS_SECRET_CHECK=true $(basename "$0") authentication
+
+  DEBUG: Optional. Set to "true" to enable shell trace mode (`set -x`).
+         Example: DEBUG=true $(basename "$0") authentication
+EOF
+}
+
+# Clones or locates the quickstart repo.
+#
+# Globals:
+#   - QUICKSTART_REPO (read-only)
+# Arguments:
+#   - $1: The name of the sample.
+# Outputs:
+#   - Echoes the absolute path to the quickstart directory.
+setup_quickstart_repo() {
+  local sample_name="$1"
+  local quickstart_dir
+
+  # If QUICKSTART_REPO is set, use it. Otherwise, clone the repo.
+  if [[ -n "${QUICKSTART_REPO:-}" ]]; then
+    # If the user provided a path, it must be a valid directory.
+    if [[ ! -d "${QUICKSTART_REPO}" ]]; then
+      echo "Error: QUICKSTART_REPO is set to '${QUICKSTART_REPO}'," \
+           "but this is not a valid directory." >&2
+      exit 1
+    fi
+    echo "Using local quickstart repository at ${QUICKSTART_REPO}" >&2
+    quickstart_dir="${QUICKSTART_REPO}"
+    if ! (cd "${quickstart_dir}" && \
+          git rev-parse --is-inside-work-tree >/dev/null 2>&1); then
+      echo "Error: QUICKSTART_REPO ('${quickstart_dir}') is not a git" \
+           "repository." >&2
+      exit 1
+    fi
+  else
+    # QUICKSTART_REPO is not set, so clone it.
+    quickstart_dir="quickstart-ios"
+    if [[ -d "${quickstart_dir}" ]]; then
+      echo "Quickstart repository already exists at ${quickstart_dir}" >&2
+    else
+      echo "Cloning quickstart repository into '${quickstart_dir}' directory..." >&2
+      # Do a partial, sparse clone to speed up CI. See
+      # https://github.blog/2020-12-21-get-up-to-speed-with-partial-clone-and-shallow-clone/
+      git clone --filter=blob:none --sparse \
+        https://github.com/firebase/quickstart-ios.git "${quickstart_dir}"
+    fi
+    (
+      cd "${quickstart_dir}"
+      echo "Ensuring sparse checkout is set for ${sample_name}..." >&2
+      # Checkout the sample directory.
+      git sparse-checkout set "${sample_name}"
+    )
+  fi
+
+  # If a branch is specified, check it out.
+  if [[ -n "${QUICKSTART_BRANCH:-}" ]]; then
+    echo "Checking out quickstart branch: ${QUICKSTART_BRANCH}" >&2
+    (
+      cd "${quickstart_dir}"
+      git fetch
+      git checkout "${QUICKSTART_BRANCH}"
+    )
+  fi
+
+  # Return the absolute path to the quickstart directory.
+  (cd "$quickstart_dir" && pwd)
+}
+
+# Updates the SPM dependency in the Xcode project based on the testing mode.
+#
+# Globals:
+#   - NIGHTLY_RELEASE_TESTING (read-only)
+#   - PRERELEASE_TESTING (read-only)
+#   - scripts_dir (read-only)
+#   - root_dir (read-only)
+# Arguments:
+#   - $1: The testing mode.
+#   - $2: The absolute path to the .xcodeproj file.
+update_spm_dependency() {
+  local release_testing_mode="$1"
+  local absolute_project_file="$2"
+
+  case "$release_testing_mode" in
+    "${NIGHTLY_RELEASE_TESTING}")
+      # For release testing, find the latest CocoaPods tag.
+      local latest_tag
+      latest_tag=$(git -C "$root_dir" tag -l "CocoaPods-*" --sort=-v:refname | \
+        grep -E '^CocoaPods-[0-9]+\.[0-9]+\.[0-9]+$' | head -n 1)
+      if [[ -z "$latest_tag" ]]; then
+        echo "Error: Could not find a 'CocoaPods-X.Y.Z' tag." >&2
+        exit 1
+      fi
+      local tag_revision
+      tag_revision=$(git -C "$root_dir" rev-list -n 1 "$latest_tag")
+      echo "Setting SPM dependency to revision for tag ${latest_tag}:" \
+           "${tag_revision}"
+      "$scripts_dir/update_firebase_spm_dependency.sh" \
+        "$absolute_project_file" --revision "$tag_revision"
+      ;;
+
+    "${PRERELEASE_TESTING}")
+      # For prerelease testing, point to the tip of the main branch.
+      echo "Setting SPM dependency to the tip of the main branch."
+      "$scripts_dir/update_firebase_spm_dependency.sh" \
+        "$absolute_project_file" --prerelease
+      ;;
+
+    *)
+      # For PR testing, point to the current commit.
+      local current_revision
+      current_revision=$(git -C "$root_dir" rev-parse HEAD)
+      echo "Setting SPM dependency to current revision: ${current_revision}"
+      "$scripts_dir/update_firebase_spm_dependency.sh" \
+        "$absolute_project_file" --revision "$current_revision"
+      ;;
+  esac
+}
+
+main() {
+  # --- Argument Parsing ---
+  if [[ -z "${1:-}" ]]; then
+    print_usage
+    exit 1
+  fi
+
+  local sample="$1"
+  local release_testing="${2-}"
+
+  # Validate release_testing argument.
+  case "$release_testing" in
+    "" | "${NIGHTLY_RELEASE_TESTING}" | "${PRERELEASE_TESTING}")
+      # This is a valid value (or empty), so do nothing.
+      ;;
+    *)
+      # This is an invalid value.
+      echo "Error: Invalid testing_mode: '${release_testing}'" >&2
+      print_usage
+      exit 1
+      ;;
+  esac
+
+  # --- Environment Setup and Validation ---
+  # Enable trace mode if DEBUG is set to 'true'
+  if [[ "${DEBUG:-false}" == "true" ]]; then
+    set -x
+  fi
+
+  # Source function to check if CI secrets are available.
+  source "$scripts_dir/check_secrets.sh"
+
+  # Some quickstarts may not need a real GoogleService-Info.plist for their
+  # tests. When QUICKSTART_REPO is set (for local runs) or BYPASS_SECRET_CHECK
+  # is true, the secrets check is skipped.
+  if [[ -z "${QUICKSTART_REPO:-}" ]] && \
+     [[ "${BYPASS_SECRET_CHECK:-}" != "true" ]] && \
+     ! check_secrets && \
+     [[ "${sample}" != "installations" ]]; then
+    echo "Skipping quickstart setup: CI secrets are not available."
+    exit 0
+  fi
+
+  # --- Main Logic ---
+  local quickstart_dir
+  quickstart_dir=$(setup_quickstart_repo "$sample")
+
+  local quickstart_project_dir="${quickstart_dir}/${sample}"
+
+  if [[ ! -d "${quickstart_project_dir}" ]]; then
+    echo "Error: Sample directory not found at '${quickstart_project_dir}'" >&2
+    exit 1
+  fi
+
+  # Find the .xcodeproj file within the sample directory.
+  # Fail if there isn't exactly one.
+  # Enable nullglob to ensure the glob expands to an empty list if no files
+  # are found.
+  shopt -s nullglob
+  local project_files=("${quickstart_project_dir}"/*.xcodeproj)
+  # Restore default globbing behavior.
+  shopt -u nullglob
+  if [[ "${#project_files[@]}" -ne 1 ]]; then
+    echo "Error: Expected 1 .xcodeproj file in" \
+         "'${quickstart_project_dir}', but found ${#project_files[@]}." >&2
+    exit 1
+  fi
+  local project_file="${project_files[0]}"
+
+  update_spm_dependency "$release_testing" "$project_file"
+}
+
+# Run the main function with all provided arguments.
+main "$@"
\ No newline at end of file