What is the difference between a beer mat and a coaster?

Generally, beer mats are more likely to have a sponsor or message as an advertising vehicle within hospitality settings, whilst coasters are often more decorative pieces, where there are custom pieces made. In practice, the two are created in the same way, are made of similar materials and are the same shape and have the same dimensions. There is also a cultural difference, in that you’ll find beer mats used as a term more commonly in the UK, whilst coaster is the term used in the USA.