Snippet to reorder countries in dropdown on WooCommerce checkout form

custom-country-dropdown.php

<?php

// DISABLE WOOCOMMERCE SORTING
add_filter( 'woocommerce_sort_countries', '__return_false' );

add_filter( 'woocommerce_countries',  'wc_custom_countries_order', 10, 1 );
function wc_custom_countries_order( $countries ) {
	
	// Replace with iso code of country AND country name (example: US | United States or GB | United Kingdom (UK)
	$countries = ['GB' => 'United Kingdom'] + ['US' => 'United States'] + ['CA' => 'Canada'] + $countries;

	return $countries;
} 

?>