diff --git a/includes/api/class-wc-rest-authentication.php b/includes/api/class-wc-rest-authentication.php
index 7e620354e94..dc3a9eafcf8 100644
--- a/includes/api/class-wc-rest-authentication.php
+++ b/includes/api/class-wc-rest-authentication.php
@@ -56,13 +56,10 @@ class WC_REST_Authentication {
 
 		$rest_prefix = trailingslashit( rest_get_url_prefix() );
 
-		// Check if our endpoint.
-		$woocommerce = ( false !== strpos( $_SERVER['REQUEST_URI'], $rest_prefix . 'wc/' ) ); // @codingStandardsIgnoreLine
-
 		// Allow third party plugins use our authentication methods.
 		$third_party = ( false !== strpos( $_SERVER['REQUEST_URI'], $rest_prefix . 'wc-' ) ); // @codingStandardsIgnoreLine
 
-		return apply_filters( 'woocommerce_rest_is_request_to_rest_api', $woocommerce || $third_party );
+		return apply_filters( 'woocommerce_rest_is_request_to_rest_api', WC()->is_rest_api_request() || $third_party );
 	}
 
 	/**
diff --git a/includes/class-woocommerce.php b/includes/class-woocommerce.php
index dcdef8fe296..f1895af763f 100644
--- a/includes/class-woocommerce.php
+++ b/includes/class-woocommerce.php
@@ -240,6 +240,29 @@ final class WooCommerce {
 		}
 	}
 
+	/**
+	 * Returns true if the request is a non-legacy REST API request.
+	 *
+	 * Legacy REST requests should still run some extra code for backwards compatibility.
+	 *
+	 * @todo: replace this function once core WP function is available: https://core.trac.wordpress.org/ticket/42061.
+	 *
+	 * @return bool
+	 */
+	public function is_rest_api_request() {
+		if ( empty( $_SERVER['REQUEST_URI'] ) ) {
+			return false;
+		}
+
+		// REST API prefix.
+		$rest_prefix = trailingslashit( rest_get_url_prefix() );
+
+		// Check if this is a WC endpoint.
+		$is_woocommerce_endpoint = ( false !== strpos( $_SERVER['REQUEST_URI'], $rest_prefix . 'wc/' ) ); // phpcs:disable WordPress.Security.ValidatedSanitizedInput.MissingUnslash, WordPress.Security.ValidatedSanitizedInput.InputNotSanitized
+
+		return apply_filters( 'woocommerce_is_rest_api_request', $is_woocommerce_endpoint );
+	}
+
 	/**
 	 * What type of request is this?
 	 *
@@ -255,7 +278,7 @@ final class WooCommerce {
 			case 'cron':
 				return defined( 'DOING_CRON' );
 			case 'frontend':
-				return ( ! is_admin() || defined( 'DOING_AJAX' ) ) && ! defined( 'DOING_CRON' ) && ! defined( 'REST_REQUEST' );
+				return ( ! is_admin() || defined( 'DOING_AJAX' ) ) && ! defined( 'DOING_CRON' ) && ! $this->is_rest_api_request();
 		}
 	}