Surfing on Sine Waves is a studio album by Polygon Window, a pseudonym for the English electronic music producer Richard D. James, better known by the alias Aphex Twin. It was originally released on 11 January 1993 by Warp. It is the second release in Warp's Artificial Intelligence series. The cover of the album features a photograph of Chapel Porth beach, Cornwall. The 2001 reissue edition includes the previously unreleased tracks, "Portreath Harbour" and "Redruth School".
Ned Raggett of AllMusic gave the album 4.5 stars out of 5, calling it "a great collection of abstract electronic/dance madness, caught somewhere between the driftiness of his more ambient works at the time and the rave-minded nuttiness of 'Digeridoo.'" Mark Richard-San of Pitchfork gave the album an 8.1 out of 10, saying, "Catchy, melodic and memorable tracks are what made the Aphex Twin so wonderful at his best; Surfing on Sine Waves has a handful of these, albeit in rough, embryonic form."
In 2012, Fact placed it at number 26 on their list of the "100 Best Albums of the 1990s".
In 2017, Pitchfork placed it at number 26 on their list of the "50 Best IDM Albums of All Time". Writing for Pitchfork, Andrew Nosnitsky said, "These days, Surfing doesn't get mentioned as often as the louder, more ambitious, 'proper' Aphex records that would follow, but it's easily as refined on a technical level—and maybe even more emotionally rewarding."