Soon synonyms such as more readily, anon, ahead of time, by preference, and from/by choice. Soon is an adverb, and its antonyms are late, belatedly, tardily, and slowly. Additionally, here are 49 synonyms for soon and words similar to it.
Anon, any day (now), any minute (now), any time (now), before long, before you know it, by and by, directly, ere long, in (less than) no time, in a jiffy, in a little while, in a minute, in a moment, in a short time, in a tick, in a twinkling, in an instant, in no time (at all), in the near future, in the twinkling of an eye, in two shakes, in two shakes of a lamb's tail, in two ticks, presently, pronto, sharpish, and shortly.
Ahead of time, already, before, beforehand, by when, earlier, early, in advance, in readiness, promptly, punctually, quickly, and speedily.
By preference, from/by choice, if I had my druthers, more readily, more willingly, preferably, and rather.