Change WooCommerce Variation Dropdown Text

You can change the default text in the product variation dropdown from ‘Choose an option‘…. to something else with the ‘woocommerce_dropdown_variation_attribute_options_args‘ filter.

Add in your functions.php

add_filter( 'woocommerce_dropdown_variation_attribute_options_args', 'bt_dropdown_choice' );
// 
/**
 * Change the custom dropdown  "Choose an option" text on the front end
 */
function bt_dropdown_choice( $args ){
        if( is_product() ) {
                $args['show_option_none'] = "Add your custom text in here"; // Change your text here
        }  
        return $args;    
}