Surface mail is a term used to refer to mail that is transported by land and sea rather than by air. This type of mail is typically used for large or heavy items that are not time-sensitive, as it is significantly slower and less expensive than airmail. Surface mail is often used for sending packages, rather than letters, as it is a more cost-effective way to transport larger or heavier items. Despite its slower speed, surface mail remains an important part of the global postal system, as it allows for the efficient and cost-effective transport of items that cannot be sent by air.