The reading is the on'yomi reading which you learned with the kanji. This is probably because this word gets attached to numbers usually, which makes it behave more like jukugo. So, you can have １回, ２回, ３回, or even １００回 if you're into that sort of thing.
I’ve been to Japan once.
I've made plans to swim from America to Japan, but they've been put on hold eight different times now.
I can’t count the number of times I’ve eaten sand.