Chillwave, love it or hate it, isn't a recent phenomenon. Exhibit A: this comparatively ancient Aphex Twin cut recorded in either the late 1980s or the very beginning of the 1990s, in a bedroom somewhere in Cornwall, England. (And nowhere close to the sun-bleached beaches of Ibiza, or the volcanic shores along the Mediterranean.) The recording quality is a bit ragged, as these tracks were mastered from cassettes that Richard D. James produced when not DJing in local clubs. But the modestly funky beats, paired with lighter-than-air female la-de-das and warm keyboard washes are the very essence of chillwave, even though Washed Out's Ernest Greene was still in short pants when this first hit record shops. Oh, and the style was called ambient techno back in those days, not chillwave.
On iTunes: Aphex Twin/"Xtal"