[General Snippets][Hide other shipping methods when “Free Shipping” is available] Hides all other shipping methods but free_shipping if it’s available. Compatible with Shipping zones.

wc-hide-all-shipping-if-free-shipping-is-available.php

/**
 * Hide shipping rates when free shipping is available.
 * Updated to support WooCommerce 2.6 Shipping Zones.
 *
 * @param array $rates Array of rates found for the package.
 * @return array
 */
function my_hide_shipping_when_free_is_available( $rates ) {
	$free = array();
	foreach ( $rates as $rate_id => $rate ) {
		if ( 'free_shipping' === $rate->method_id ) {
			$free[ $rate_id ] = $rate;
			break;
		}
	}
	return ! empty( $free ) ? $free : $rates;
}
add_filter( 'woocommerce_package_rates', 'my_hide_shipping_when_free_is_available', 100 );

Warning! I found out that woocommerce_package_rates hook is not fired everytime, but only when you change items or quantity of items in your cart.

Source: https://stackoverflow.com/a/26296461/4380588

@faiyazalam this is not true to me, using woocommerce 3.3.4, on wp4.9.4, Bistro theme.

On line #18, where you call the add_filter( ... ), you are missing the arguments for $accepted_args, it should be specified to 2, since the filter is called with 2 arguments:

from wp-content/plugins/woocommerce/includes/class-wc-shipping.php

$package['rates'] = apply_filters( 'woocommerce_package_rates', $package['rates'], $package );

add_filter( 'woocommerce_package_rates', 'my_hide_shipping_when_free_is_available', 100, 2 );

Hope I am not missing anything.

Does not seem to be working anymore with Table Rate Shipping when the rules allow free shipping.

Does not work for Woocommerce 4.0

/**

• Hide shipping rates when free shipping is available.
• Updated to support WooCommerce 2.6 Shipping Zones.
• @param array $rates Array of rates found for the package.
• @return array
  */
  function my_hide_shipping_when_free_is_available( $rates ) {
  $free = array();
  foreach ( $rates as $rate_id => $rate ) {
  if ( 'free_shipping' === $rate->method_id ) {
  $free[ $rate_id ] = $rate;
  break;
  }
  }
  return ! empty( $free ) ? $free : $rates;
  }
  $package['rates'] = apply_filters( 'woocommerce_package_rates', $package['rates'], $package );
  add_filter( 'woocommerce_package_rates', 'my_hide_shipping_when_free_is_available', 100, 2 );

For purposes of facilitating copy and paste, here is the code from @JoyMovil above, but then properly formatted:

/**
 * Hide shipping rates when free shipping is available.
 * Updated to support WooCommerce 2.6 Shipping Zones.
 * 
 * Change `my_` part of function-name to something unique to your own site
 *
 * @param array $rates Array of rates found for the package.
 * @return array
 */
function my_hide_shipping_when_free_is_available( $rates ) {
	$free = array();
	foreach ( $rates as $rate_id => $rate ) {
		if ( 'free_shipping' === $rate->method_id ) {
			$free[ $rate_id ] = $rate;
			break;
		}
	}
	return ! empty( $free ) ? $free : $rates;
}

$package['rates'] = apply_filters( 'woocommerce_package_rates', $package['rates'], $package );

add_filter( 'woocommerce_package_rates', 'my_hide_shipping_when_free_is_available', 100, 2 );