CartRules One Shipping Class in Cart for WooCommerce

This plugin stops customers from mixing products with different shipping classes in the same order. If a product is already in the cart, adding a product from a different shipping class will either be blocked, or the cart will be emptied first, depending on the option you choose.

This is useful for stores where mixing shipping classes causes shipping calculation problems, for example freight vs. standard items, or products that must ship in separate boxes or from different warehouses.

Once activated, go to WooCommerce > Settings > CartRules > One Shipping Class in Cart to turn the restriction on and choose what should happen.

Works with both the classic, shortcode-based cart and checkout, and the newer WooCommerce Cart and Checkout blocks.