Keep only a specific payment method for Local Pickup shipping method in WooCommerce

function my_custom_available_payment_gateways( $gateways ) {

    $chosen_shipping_rates = WC()->session->get( 'chosen_shipping_methods' );

    // When 'local delivery' has been chosen as shipping rate
    if ( in_array( 'local_delivery', $chosen_shipping_rates ) ) :

        // Remove bank transfer payment gateway
        unset( $gateways['bacs'] );

    endif;

    return $gateways;

}
add_filter( 'woocommerce_available_payment_gateways', 'my_custom_available_payment_gateways' ); 

This code doesn’t work for me. How can I achieve that?

Answer

Try the following instead:

add_filter( 'woocommerce_available_payment_gateways', 'my_custom_available_payment_gateways', 10, 1 );
function my_custom_available_payment_gateways( $available_gateways ) {
    if( is_admin() ) return $available_gateways; // Only for frontend
    
    $local_found = false; // Initializing

    // Loop through chosen shipping method rates
    foreach ( WC()->session->get( 'chosen_shipping_methods' ) as $chosen_shipping_rate_id ) {
        if( strpos( $chosen_shipping_rate_id, 'local_pickup' ) !== false || strpos( $chosen_shipping_rate_id, 'local_delivery' ) !== false ) {
            $local_found = true; // Local pickup/delivery found
            break; // Stop the loop
        }
    }
    
    // If Local pickup/delivery is the chosen shipping method
    if( $local_found ) {
        // Loop through available payment methods
        foreach ( $available_gateways as $payment_method_id => $payment_label ) {
            // Remove all payement methods except "cheque"
            if ( 'cheque' !== $payment_method_id ) {
                unset( $available_gateways[$payment_method_id] );
            }
        }
    }

    return $available_gateways;
}

Code goes in functions.php file of the active child theme (or active theme). Tested and works.