Snippet to hide WooCommerce shipping rates if free shipping is available

hide-shipping-rates.php

<?php

// ONLY SHOW FREE SHIPPING METHOD IF AVAILABLE
add_filter( 'woocommerce_package_rates', 'only_show_free_shipping', 100 );
function only_show_free_shipping( $rates ) {
	$free_rates = array();
	foreach ( $rates as $rate_id => $rate ) {
		if ( 'free_shipping' === $rate->method_id ) {
			$free_rates[ $rate_id ] = $rate;
			break;
		}
	}
	return ! empty( $free_rates ) ? $free_rates : $rates;
}

// SHOW FREE SHIPPING METHODS AS WELL AS LOCAL PICKUP AND ZERO FLAT RATES
add_filter( 'woocommerce_package_rates', 'custom_hide_all_shipping_when_free_is_available' );
function custom_hide_all_shipping_when_free_is_available( $shipping_rates) {
  $free_rates = array();
  $free_shipping_available = false;

  foreach ( $shipping_rates as $key => $rate ) {
    if ( 0 == $rate->cost) {
      $free_shipping_available = true;
			$free_rates[ $key ] = $rate;
    }
  }

  if ( $free_shipping_available ) {
    return $free_rates;
  }
  return $shipping_rates;
}

?>