--- a/chrome/browser/resources/settings/privacy_page/privacy_page.html
+++ b/chrome/browser/resources/settings/privacy_page/privacy_page.html
@@ -69,21 +69,6 @@
             sub-label="$i18n{permissionsPageDescription}"
             on-click="onPermissionsPageClick_"
             role-description="$i18n{subpageArrowRoleDescription}"></cr-link-row>
-        <template is="dom-if" if="[[!isPrivacySandboxRestricted_]]">
-          <cr-link-row id="privacySandboxLinkRow"
-              start-icon="settings20:experiment"
-              class="hr"
-              label="$i18n{privacySandboxTitle}"
-              sub-label="[[computePrivacySandboxSublabel_(
-                  prefs.privacy_sandbox.*)]]"
-              on-click="onPrivacySandboxClick_"
-              external
-              role-description="$i18n{subpageArrowRoleDescription}">
-          </cr-link-row>
-          <a id="privacySandboxLink" href="privacySandbox"
-              target="_blank" tabindex="-1" aria-disabled="true"
-              role="none"></a>
-        </template>
       </div>
 
 <if expr="use_nss_certs">
--- a/components/privacy_sandbox/privacy_sandbox_prefs.cc
+++ b/components/privacy_sandbox/privacy_sandbox_prefs.cc
@@ -66,7 +66,7 @@ namespace privacy_sandbox {
 
 void RegisterProfilePrefs(PrefRegistrySimple* registry) {
   registry->RegisterBooleanPref(
-      prefs::kPrivacySandboxApisEnabled, true,
+      prefs::kPrivacySandboxApisEnabled, false,
       user_prefs::PrefRegistrySyncable::SYNCABLE_PREF);
   registry->RegisterBooleanPref(prefs::kPrivacySandboxApisEnabledV2, false);
   registry->RegisterBooleanPref(
--- a/components/privacy_sandbox/privacy_sandbox_settings.cc
+++ b/components/privacy_sandbox/privacy_sandbox_settings.cc
@@ -335,45 +335,10 @@ bool PrivacySandboxSettings::IsPrivateAg
 }
 
 bool PrivacySandboxSettings::IsPrivacySandboxEnabled() const {
-  // If the delegate is restricting access the Privacy Sandbox is disabled.
-  if (delegate_->IsPrivacySandboxRestricted())
-    return false;
-
-  // For Measurement and Relevance APIs, we explicitly do not require the
-  // underlying pref to be enabled if there is a local flag enabling the APIs to
-  // allow for local testing.
-  bool should_override_setting_for_local_testing = base::FeatureList::IsEnabled(
-      privacy_sandbox::kOverridePrivacySandboxSettingsLocalTesting);
-
-  // Which preference is consulted is dependent on whether release 3 of the
-  // settings is available.
-  if (base::FeatureList::IsEnabled(privacy_sandbox::kPrivacySandboxSettings3)) {
-    // For Privacy Sandbox Settings 3, APIs are disabled in incognito.
-    if (incognito_profile_)
-      return false;
-
-    if (should_override_setting_for_local_testing) {
-      return true;
-    }
-
-    // For Privacy Sandbox Settings 3, APIs may be restricted via the delegate.
-    // The V2 pref was introduced with the 3rd Privacy Sandbox release.
-    return pref_service_->GetBoolean(prefs::kPrivacySandboxApisEnabledV2);
-  }
-
-  if (should_override_setting_for_local_testing)
-    return true;
-
-  return pref_service_->GetBoolean(prefs::kPrivacySandboxApisEnabled);
+  return false;
 }
 
 void PrivacySandboxSettings::SetPrivacySandboxEnabled(bool enabled) {
-  // Only apply the decision to the appropriate preference.
-  if (base::FeatureList::IsEnabled(privacy_sandbox::kPrivacySandboxSettings3)) {
-    pref_service_->SetBoolean(prefs::kPrivacySandboxApisEnabledV2, enabled);
-  } else {
-    pref_service_->SetBoolean(prefs::kPrivacySandboxApisEnabled, enabled);
-  }
 }
 
 bool PrivacySandboxSettings::IsTrustTokensAllowed() {
--- a/content/browser/aggregation_service/aggregation_service_features.cc
+++ b/content/browser/aggregation_service/aggregation_service_features.cc
@@ -9,7 +9,7 @@ namespace content {
 // Enables the Aggregation Service. See crbug.com/1207974.
 BASE_FEATURE(kPrivacySandboxAggregationService,
              "PrivacySandboxAggregationService",
-             base::FEATURE_ENABLED_BY_DEFAULT);
+             base::FEATURE_DISABLED_BY_DEFAULT);
 
 const base::FeatureParam<std::string>
     kPrivacySandboxAggregationServiceTrustedServerUrlParam{
--- a/third_party/blink/common/features.cc
+++ b/third_party/blink/common/features.cc
@@ -106,7 +106,7 @@ BASE_FEATURE(kBlockingDownloadsInAdFrame
 // Controls whether the Conversion Measurement API infrastructure is enabled.
 BASE_FEATURE(kConversionMeasurement,
              "ConversionMeasurement",
-             base::FEATURE_ENABLED_BY_DEFAULT);
+             base::FEATURE_DISABLED_BY_DEFAULT);
 
 // Controls whether LCP calculations should exclude low-entropy images. If
 // enabled, then the associated parameter sets the cutoff, expressed as the