Snapchat will overtake Facebook among 18- to 24-year-olds this year, according to eMarketer’s latest forecast on social network usage.

The number of Snapchat users in the UK will reach 16.2 million this year, of which 5.0 million (or nearly 31%) will be between 18 and 24. By comparison, the number of UK Facebook users ages 18 to 24 will total 4.5 million, down 1.8% over 2017. Instagram will have 4.2 million users in this cohort, and 2.6 million will use Twitter. While Facebook-owned Instagram is growing its younger user base, our forecast indicates Snapchat will retain the upper hand in that category in the coming years.

Facebook is still adding monthly users overall, but older age groups are mainly responsible for this. Overall, there will be 32.7 million Facebook users in the UK this year, up 2.0% over 2017.

Our forecast also shows that mobile Facebook user growth has started to level off, suggesting that many younger social network users are forgoing Facebook altogether in favor of more appealing mobile-first alternatives.

“These so-called Facebook-nevers are eating into Facebook’s user growth significantly,” said eMarketer senior analyst Bill Fisher. “While the media giant’s Instagram purchase looks to have been a shrewd move in as much that it’s picking up that young user base, it’s struggling to hold onto the coattails of Snapchat among these cohorts.”