diff --git a/features/plugin-update.feature b/features/plugin-update.feature
index 46513e14..4567d938 100644
--- a/features/plugin-update.feature
+++ b/features/plugin-update.feature
@@ -371,6 +371,67 @@ Feature: Update WordPress plugins
       Success: Updated 2 of 2 plugins.
       """
 
+  @require-wp-5.2
+  Scenario: Updating several plugins downloads their packages side by side
+    Given a WP install
+    And an empty cache
+    And I run `wp plugin delete akismet`
+
+    When I run `wp plugin install health-check --version=1.5.0`
+    Then STDOUT should not be empty
+
+    When I run `wp plugin install wordpress-importer --version=0.5`
+    Then STDOUT should not be empty
+
+    When I try `wp plugin update --all`
+    Then STDOUT should contain:
+      """
+      Downloading 2 packages...
+      """
+    And STDOUT should contain:
+      """
+      Using cached file
+      """
+    And STDOUT should contain:
+      """
+      Success: Updated 2 of 2 plugins.
+      """
+
+    When I run `wp plugin install health-check --version=1.5.0 --force`
+    And I run `wp plugin install wordpress-importer --version=0.5 --force`
+    And I try `wp plugin update --all`
+    Then STDOUT should not contain:
+      """
+      Downloading 2 packages...
+      """
+    And STDOUT should contain:
+      """
+      Success: Updated 2 of 2 plugins.
+      """
+
+  @require-wp-5.2
+  Scenario: Updating a single plugin downloads its package on its own
+    Given a WP install
+    And an empty cache
+    And I run `wp plugin delete akismet`
+
+    When I run `wp plugin install wordpress-importer --version=0.5`
+    Then STDOUT should not be empty
+
+    When I try `wp plugin update --all`
+    Then STDOUT should not contain:
+      """
+      Downloading 1 package
+      """
+    And STDOUT should not contain:
+      """
+      Using cached file
+      """
+    And STDOUT should contain:
+      """
+      Success: Updated 1 of 1 plugins.
+      """
+
   @require-wp-5.2 @skip-windows
   Scenario: Failed plugin update keeps JSON output parseable
     Given a WP install
diff --git a/features/theme-update.feature b/features/theme-update.feature
index c93d9377..a5c5ab91 100644
--- a/features/theme-update.feature
+++ b/features/theme-update.feature
@@ -258,6 +258,32 @@ Feature: Update WordPress themes
       Success: Updated 2 of 2 themes.
       """
 
+  @require-wp-4.5
+  Scenario: Updating several themes downloads their packages side by side
+    Given a WP install
+    And an empty cache
+    And I run `wp theme delete --all --force`
+
+    When I run `wp theme install storefront --version=1.0.0`
+    Then STDOUT should not be empty
+
+    When I run `wp theme install twentytwelve --version=1.0`
+    Then STDOUT should not be empty
+
+    When I try `wp theme update --all`
+    Then STDOUT should contain:
+      """
+      Downloading 2 packages...
+      """
+    And STDOUT should contain:
+      """
+      Using cached file
+      """
+    And STDOUT should contain:
+      """
+      Success: Updated 2 of 2 themes.
+      """
+
   Scenario: Skip theme update when theme directory is a VCS checkout
     Given a WP install
     And I run `wp theme install twentytwelve --version=3.0 --force`
diff --git a/src/WP_CLI/CommandWithUpgrade.php b/src/WP_CLI/CommandWithUpgrade.php
index 4ad5032b..b7260c72 100755
--- a/src/WP_CLI/CommandWithUpgrade.php
+++ b/src/WP_CLI/CommandWithUpgrade.php
@@ -807,6 +807,10 @@ function ( $item ) {
 			foreach ( $items_to_update as $item ) {
 				$cache_manager->whitelist_package( $item['update_package'], $this->item_type, $item['name'], $item['update_version'] );
 			}
+			// Fetch the packages side by side before the upgrader asks for them one at a time.
+			if ( method_exists( $cache_manager, 'prefetch' ) ) {
+				$cache_manager->prefetch( wp_list_pluck( $items_to_update, 'update_package' ) );
+			}
 			$upgrader = $this->get_upgrader( $assoc_args );
 			// Ensure the upgrader uses the download offer present in each item.
 			$transient_filter = function ( $transient ) use ( $items_to_update ) {