Yes, you can check a cooler as one of your two free checked bags on Southwest Airlines, provided it meets the standard weight and size requirements. The cooler must weigh 50 pounds (22.7 kg) or less and have a maximum physical size of 62 inches (length + width + height). It is essential that the cooler is securely fastened with tape or a heavy-duty strap to prevent it from opening during transit. Furthermore, per TSA and airline safety regulations, you cannot use standard "wet" ice inside the cooler as it will leak when it melts; instead, use reusable gel packs or dry ice (dry ice is limited to 5.5 pounds and must be in a vented container labeled "Dry Ice"). If the cooler contains food, ensure it is packed tightly to avoid shifting. Southwest is particularly popular for this because, unlike other airlines that charge $30–$50 per bag, they allow you to transport your tailgating or camping supplies for free as long as you stay within the weight limit.