Check if ANY coupon code is applied in woocommerce as suggested by @Anand, you can use WC()->cart->get_coupons(). This will return all the coupons if there are any in the cart. However, as I've check woocommerce plugin source code, get_coupons() is using WP_Query. It's really not a big deal if there's no other better way. Here's a better way. We can access a public variable of the cart applied ...