diff --git a/.github/workflows/conformance-test.yaml b/.github/workflows/conformance-test.yaml
index a3df27da0c21..1ef82b98026b 100644
--- a/.github/workflows/conformance-test.yaml
+++ b/.github/workflows/conformance-test.yaml
@@ -20,7 +20,7 @@ jobs:
           persist-credentials: false
       - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
         with:
-          node-version: 14
+          node-version: 22
       - run: node --version
       - run: cd handwritten/storage && npm install
       - run: cd handwritten/storage && npm run conformance-test
diff --git a/.github/workflows/conformance.yaml b/.github/workflows/conformance.yaml
index 0532ef0a003b..6b775d3268d1 100644
--- a/.github/workflows/conformance.yaml
+++ b/.github/workflows/conformance.yaml
@@ -34,7 +34,7 @@ jobs:
         working-directory: handwritten/bigtable
     strategy:
       matrix:
-        node: [ 18, 20 ]
+        node: [ 20, 22 ]
     steps:
     - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
       with:
diff --git a/.github/workflows/issues-no-repro.yaml b/.github/workflows/issues-no-repro.yaml
index f65c54ea1dbd..258b6585bf4c 100644
--- a/.github/workflows/issues-no-repro.yaml
+++ b/.github/workflows/issues-no-repro.yaml
@@ -18,7 +18,7 @@ jobs:
           persist-credentials: false
       - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
         with:
-          node-version: 18
+          node-version: 22
       - run: npm install
         working-directory: ./.github/scripts
       - uses: actions/github-script@ed597411d8f924073f98dfc5c65a23a2325f34cd # v8
diff --git a/.github/workflows/mandatory-conformance.yaml b/.github/workflows/mandatory-conformance.yaml
index 6cd546a7dc72..e86bacd24a98 100644
--- a/.github/workflows/mandatory-conformance.yaml
+++ b/.github/workflows/mandatory-conformance.yaml
@@ -34,7 +34,7 @@ jobs:
         working-directory: handwritten/bigtable
     strategy:
       matrix:
-        node: [ 18, 20 ]
+        node: [ 20, 22 ]
     steps:
     - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
       with:
diff --git a/.github/workflows/update-api-list.yaml b/.github/workflows/update-api-list.yaml
index 52095638468a..0254d3035e26 100644
--- a/.github/workflows/update-api-list.yaml
+++ b/.github/workflows/update-api-list.yaml
@@ -15,7 +15,7 @@ jobs:
           persist-credentials: false
       - uses: actions/setup-node@48b55a011bda9f5d6aeb4c2d9c7362e8dae4041e # v6.4.0
         with:
-          node-version: 18
+          node-version: 22
       - run: npm install
       - run: npm run generate
         env:
diff --git a/.pnpmfile.cjs b/.pnpmfile.cjs
deleted file mode 100644
index 01999c7fb598..000000000000
--- a/.pnpmfile.cjs
+++ /dev/null
@@ -1,72 +0,0 @@
-module.exports = {
-  hooks: {
-    readPackage(pkg, context) {
-      // Check if this package has yargs as a dependency or devDependency
-      if (pkg.dependencies && pkg.dependencies.yargs) {
-        mutateYargs(pkg.dependencies, pkg.name, 'dependencies', context);
-      }
-      if (pkg.devDependencies && pkg.devDependencies.yargs) {
-        mutateYargs(pkg.devDependencies, pkg.name, 'devDependencies', context);
-      }
-
-      // C8 broke Node 18 compatibility the week of July 20th 2026. 
-      // Until we complete the upgrade, we need this workaround to enable CI
-      // to continue running.
-      //
-      // TODO: Remove this workaround after Node 22 upgrade.
-      if (pkg.dependencies && pkg.dependencies.c8) {
-        mutateC8(pkg.dependencies, pkg.name, 'dependencies', context);
-      }
-      if (pkg.devDependencies && pkg.devDependencies.c8) {
-        mutateC8(pkg.devDependencies, pkg.name, 'devDependencies', context);
-      }
-
-      // Check if this package has brace-expansion as a dependency or devDependency
-      if (pkg.dependencies && pkg.dependencies['brace-expansion']) {
-        mutateBraceExpansion(pkg.dependencies, pkg.name, 'dependencies', context);
-      }
-      if (pkg.devDependencies && pkg.devDependencies['brace-expansion']) {
-        mutateBraceExpansion(pkg.devDependencies, pkg.name, 'devDependencies', context);
-      }
-      return pkg;
-    }
-  }
-};
-
-function mutateBraceExpansion(deps, pkgName, depType, context) {
-  const nodeVersion = process.version;
-  const majorVersion = parseInt(nodeVersion.replace('v', '').split('.')[0], 10);
-
-  if (majorVersion === 18) {
-    if (deps['brace-expansion'] && deps['brace-expansion'].startsWith('^5.')) {
-      console.log(`[pnpmfile] Node.js version is 18. Overriding brace-expansion to 5.0.7 in ${pkgName}`);
-      deps['brace-expansion'] = '5.0.7';
-    }
-  }
-}
-
-function mutateYargs(deps, pkgName, depType, context) {
-  const nodeVersion = process.version;
-  const majorVersion = parseInt(nodeVersion.replace('v', '').split('.')[0], 10);
-  
-  if (majorVersion >= 24) {
-    console.log(`[pnpmfile] Node.js version is ${nodeVersion} (>= 24). Overriding yargs to 18.0.0 in ${pkgName}`);
-    deps.yargs = '18.0.0';
-  }
-}
-
-/**
- * Override C8 dependency for versions of Node <=18 to enable CI to continue functioning.
- * 
- * Otherwise, continue to use 10+ version.
- */
-function mutateC8(deps, pkgName, depType, context) {
-  const nodeVersion = process.version;
-  const majorVersion = parseInt(nodeVersion.replace('v', '').split('.')[0], 10);
-  
-  if (majorVersion <= 18) {
-    console.log(`[pnpmfile] Node.js version is ${nodeVersion} (<= 18). Overriding c8 to ^9.1.0 in ${pkgName}`);
-    deps.c8 = '^9.1.0';
-  }
-}
-
diff --git a/ci/run_single_test.sh b/ci/run_single_test.sh
index 662a1184f347..51c84bc0483d 100755
--- a/ci/run_single_test.sh
+++ b/ci/run_single_test.sh
@@ -40,15 +40,8 @@ if [ ${BUILD_TYPE} != "presubmit" ]; then
 fi
 
 # Install dependencies
-# Normalize POSIX paths to Windows-compatible mixed paths (forward slashes) on Windows Git Bash
-# so native Node.js and pnpm processes can resolve .pnpmfile.cjs without segmentation faults.
-PNPMFILE_PATH="${PROJECT_ROOT}/.pnpmfile.cjs"
-if command -v cygpath >/dev/null 2>&1; then
-    PNPMFILE_PATH=$(cygpath -m "${PNPMFILE_PATH}")
-fi
-
-echo "pnpm install --ignore-scripts --engine-strict --prod --pnpmfile \"${PNPMFILE_PATH}\"; pnpm install --pnpmfile \"${PNPMFILE_PATH}\""
-pnpm install --ignore-scripts --engine-strict --prod --pnpmfile "${PNPMFILE_PATH}"; pnpm install --pnpmfile "${PNPMFILE_PATH}"
+echo "pnpm install --ignore-scripts --engine-strict --prod; pnpm install"
+pnpm install --ignore-scripts --engine-strict --prod; pnpm install
 
 
 retval=0
diff --git a/core/generator/gapic-generator-typescript/baselines-esm/duplicate_methods_test-esm/package.json b/core/generator/gapic-generator-typescript/baselines-esm/duplicate_methods_test-esm/package.json
index 0ab004c938fe..999b16f2d6ac 100644
--- a/core/generator/gapic-generator-typescript/baselines-esm/duplicate_methods_test-esm/package.json
+++ b/core/generator/gapic-generator-typescript/baselines-esm/duplicate_methods_test-esm/package.json
@@ -98,6 +98,6 @@
     "webpack-cli": "^6.0.1"
   },
   "engines": {
-    "node": ">=18"
+    "node": ">=22"
   }
 }
diff --git a/core/packages/gapic-node-processing/templates/bootstrap-templates/package.json b/core/packages/gapic-node-processing/templates/bootstrap-templates/package.json
index b4f734f77a57..e728738a2bf4 100644
--- a/core/packages/gapic-node-processing/templates/bootstrap-templates/package.json
+++ b/core/packages/gapic-node-processing/templates/bootstrap-templates/package.json
@@ -62,6 +62,6 @@
     "typescript": "^5.8.2"
   },
   "engines": {
-    "node": ">=18"
+    "node": ">=22"
   }
 }
diff --git a/package.json b/package.json
index 3cabdb748dac..6c7a910346df 100644
--- a/package.json
+++ b/package.json
@@ -49,6 +49,6 @@
     "prettier": "^3.3.3"
   },
   "engines": {
-    "node": ">=18"
+    "node": ">=20"
   }
 }