Family name ท่าน้ำ (Pier 
, Thanam 
, ท่าน้ำ) , in all the world, is quite a common surname. The surname ท่าน้ำ is habitual in Marshall Islands, where it is quite a common surname, San Marino, and Guernsey. Measured by absolute frequency, it is the most numerous in the United States, India, and Germany. More prevalently, ท่าน้ำ is the forename as well as the last name.
| VARIANT | COUNTRY |
|---|---|
| Pier | Germany, Dominican Republic, Italy, United States, India |
| Thanam | France, United States, India, Sri Lanka, Malaysia |