Английский Этимологический словарь - surf (n.)

- 1685, probably from earlier suffe (1599), of uncertain origin. Originally used in reference to the coast of India, hence perhaps of Indic origin. Or perhaps a phonetic respelling of sough, which meant "a rushing sound." The verb meaning "ride the crest of a wave" is from 1917; surfer, surfing both from 1955. In the Internet sense, first recorded 1993.