How to Sort WooCommerce Shipping Options by Ascending Cost with Free Shipping at the End?

The code given below reorders WooCommerce shipping methods, arranges the rates from low to high order cost, and also ensures that free shipping methods are displayed at the end in the sorted shipping options.

add_filter( 'woocommerce_package_rates' , 'ts_sort_shipping_method_by_cost_zero_empty_cost_last', 10, 2 );
function ts_sort_shipping_method_by_cost_zero_empty_cost_last( $rates, $package ) {
    if ( empty( $rates ) || ! is_array( $rates ) ) return;

    // Sort shipping methods based on cost
    uasort( $rates, function ( $a, $b ) {
        if ( $a == $b ) return 0;
        return ( $a->cost < $b->cost ) ? -1 : 1;
    } );

    $free = $zero = []; // Initializing

    // Loop through shipping rates
    foreach ( $rates as $rate_key => $rate ) {
        // For "free shipping" methods
        if ( 'free_shipping' === $rate->method_id ) {
            // set them on a separated array
            $free[$rate_key] = $rate;

            // Remove "Free shipping" method from $rates array
            unset($rates[$rate_key]);
        } 
        // For other shipping rates with zero cost
        elseif ( $rate->cost == 0 ) {
            // set them on a separated array
            $zero[$rate_key] = $rate;

            // Remove the current method from $rates array
            unset($rates[$rate_key]);
        }
    }

    // Merge zero cost and "free shipping" methods at the end if they exist
    return ! empty( $free ) || ! empty( $zero ) ? array_merge($rates, $zero, $free) : $rates;
}

Output

Here is the output of the sorted shipping options arranged from low to high cost, followed by free or zero-cost options always at the end of the list.

The below output shows that the default options of how it was arranged before applying the code.

You can also try to clearly show the shipping costs as ‘0’ for free shipping methods. Look into our post that will help you to display $0.00 amount for free shipping rates in WooCommerce.