My eldest went through a phase of always coming into bed with me, it didn't bother me at first but after a while i wanted the bed to myself so  everytime she got into bed with me i would take her back to her own bed, no eye contact no talking and tuck her in, i probably did this ten times the first night but it became less and less each night and eventually she stopped coming into my bed, it took a lot of persistance and getting out of bed in the middle of the night when i really couldn't be bothered but it did work and i was relieved to have my bed back....good luck

We have never done the co sleeping thing with any of our kids, and yet our 2 year old is often sleeping in our bed when she wakes up at night.

We plan on solving this problem by getting her a single bed, and when she wakes up or is going to bed, laying with her on her bed until she goes to sleep.  Maybe you could try the same sort of thing.

For a young child of this age, I would recommend guard rails for the bed so they don't roll out and hurt themselves.